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Electronics/Transistors

Transistor
A transistor is a solid state device made by joining three positive-type and negative-type semiconductors together. In general, all transistors have three pins: base, collector, and emitter. Transistor is a bi-polar device that is a transistor with two junctions namely BE and CE DE EE FE. In theory we take a specified formulae incorporate this with using any type of meter in figuring the mathematical solution.
 * Electronic_component_transistors.jpg

Construction
A lightly doped region called base is sandwiched between two regions called the emitter and collector respectively. The collector handles large quantities of current, hence its dopant concentration is the highest. The emitter's dopant concentration is slightly lesser, but its area is larger to provide for more current than the collector. The collector region should be heavily doped because electron-hole pairs recombine in that region, while the emitter is not such a region. We can have two varieties in this kind of transistor.

NPN Transistor
An NPN transistor is made by joining one positive-type semiconductor in between two negative-type semiconductors. Here a lightly doped p-type semiconductor (semiconductor with more holes than electrons) is sandwiched between two well-doped n-type regions. It is like two pn-junctions facing away. An IEEE symbol for the NPN transistor is shown here. The arrow between the base and emitter is in the same direction as current flowing between the base-emitter junction. Power dissipated in the transistor is
 * $$P=V_{CE}I_C$$, where $$V_{CE}$$ is the voltage between the collector and the emitter and $$I_C$$ is the collector current.

 * NPN_BJT.svg
 * BJT_symbol_NPN.svg

PNP Transistor
A PNP transistor is made by sandwiching a negative-type semiconductor in between two positive-type semiconductors.
 * PNP_BJT.svg
 * BJT_symbol_PNP.svg

Amplifier
A transistor conducts current when the base voltage is greater than BE junction's voltage. Current is non zero.
 * $$I_B \neq 0$$
 * $$I_C = \alpha I_E$$
 * $$I_C = \beta I_B$$

Switch
A transistor conducts current when the base voltage is greater than BE junction's voltage. Current is non zero. This corresponds to a closed switch. A transistor does not conduct current when the base voltage is less than BE junction's voltage. Current is zero. This correspond to an open switch.

title: Electronics/Transistors


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Talk:Authoring Webpages

I have put my declaration of intent in the Rationale in the book's first pages (after the table of contents). This is a book about authoring, not about designing or programming. Some coding should be discussed (specifically, HTML mark-up and CSS coding), and the consequences of graphical design and typography will also be treated, though in optional chapters (you don't need to be able to see to create a webpage).

My weaknesses are in the didactic and linguistic realms: I am not a teacher, nor am I a native speaker of English.

I request that you will let me finish the main text of this more or less uninterupted, so that the unity of my message remains at least until the first draft of the work is finished. After that, I would be honoured if people took this work apart.Branko 22:20, 26 Mar 2004 (UTC)

''Thank you for starting this book. It looks good so far.'' I posted the "merge" notice, but now that I look closer, I think this might be different enough in emphasis to be worth keeping as 2 books -- perhaps Web Design should be the sequel to Authoring Webpages ? --DavidCary 03:41, 8 November 2005 (UTC)

I agree that this should NOT be merged with Web Design; if anything, I started this as the anti-dote to books that treat web authoring like it is a graphic design or programming discipline.

I stopped working on this a while ago, not because I lost interest, but because I lost my idea of how to proceed. A lot of what I wrote here is in the subconscious of many a web expert, but little of it was ever put in words and collected in one place.

The thing with books, even if they are collaberately produced, is that they still need a single vision. A merge with the book you mentioned would probably blur that vision too much.

I have got a question for you. I wanted to work on this book until it had a modicum of editability, and only then link to it from other wikibooks pages. Do you think that is the right approach, or should I make it public earlier? Thanks for your insights.--Branko 17:57, 4 January 2006 (UTC)

 * If you don't want anyone else editing it, you should keep the text on your own computer. As soon as you post it to Wikipedia, you are giving us permission to edit it. I would like you to make it public as soon as you have an outline. If someone else can fill in part of the outline faster than you can, that's great.
 * I like the "Rationale" section. If everyone knows the scope of the book, then people other than yourself can recognize when well-meaning individuals start blurring the vision of the book. We can chop out bloat and move it to a more appropriate book.
 * I would like a little more detail on the exact scope of the book (what the book assumes the reader already knows Authoring webpages/Requirements, what the book is intended to teach, and what is outside the scope of the book). (Or is this something that only editors are interested in, not readers, and so should go on this talk page?). Naturally, for those people who really want to write up something that is just barely outside the scope of this book, it would be nice to point them towards other books more appropriate for those topics. --DavidCary 06:25, 8 January 2006 (UTC)

Cleanup
The work need a cleanup to move the structure and content away from the course format into a book format. --Panic (talk) 03:57, 1 May 2008 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Authoring Webpages


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File:Electronics ResistanceEX2.PNG

Explaining relation between cross sectional area and resistance

title: File:Electronics ResistanceEX2.PNG


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File:Electronics ResistanceEX1.PNG

Example one for resistance of materials

title: File:Electronics ResistanceEX1.PNG


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Electronics/RCL time domain simple

Figure 1: RCL circuit

When the switch is closed, a voltage step is applied to the RCL circuit. Take the time the switch was closed to be 0s such that the voltage before the switch was closed was 0 volts and the voltage after the switch was closed is a voltage V. The voltage across the capacitor consists of a forced response $$v_f$$ and a natural response $$v_n$$ such that: $$ v_c=v_f+v_n $$

The forced response is due to the switch being closed, which is the voltage V for $$t\ge0$$. The natural response depends on the circuit values and is given below:

Define the pole frequency $$\omega_n$$ and the dampening factor $$\alpha$$ as: $$ \alpha=\frac{R}{2L} $$ $$ \omega_n=\frac{1}{\sqrt{LC}} $$

Depending on the values of $$\alpha$$ and $$\omega_n$$ the system can be characterized as:

1. If $$\alpha > \omega_n$$ the system is said to be overdamped. The solution for the system has the form: $$ v_n(t)=A_1e^{\big(-\alpha+\sqrt{\alpha^2-\omega_n^2}\big)t}+A_2e^{\big(-\alpha-\sqrt{\alpha^2-\omega_n^2}\big)t} $$

2. If $$\alpha = \omega_n$$ the system is said to be critically damped The solution for the system has the form: $$ v_n(t)=Be^{-\alpha t} $$

3. If $$\alpha < \omega_n$$ the system is said to be underdamped The solution for the system has the form: $$ v_n(t)=e^{-\alpha t}\big[B_1\cos(\sqrt{\omega_n^2-\alpha^2} t)+B_2\sin(\sqrt{\omega_n^2-\alpha^2} t)\big] $$

How do you calculate these equations?

Example
Given the following values what is the response of the system when the switch is closed?

First calculate the values of $$\alpha$$ and $$\omega_n$$: $$ \alpha=\frac{R}{2L}=1000 $$ $$ \omega_n=\frac{1}{\sqrt{LC}}\approx 4472 $$

From these values note that $$\alpha < \omega_n$$. The system is therefore underdamped. The equation for the voltage across the capacitor is then: $$ v_c(t)=1+e^{-1000t}\big[B_1\cos(4359t)+B_2\sin(4359t)\big] $$

Before the switch was closed assume that the capacitor was fully discharged. This implies that v(t)=0 at the instant the switch was closed (t=0). Substituting t=0 into the previous equation gives: $$ 0=1+B_1 $$ Therefore $$B_1=-1$$. Similarly at the instant the switch is closed, the current in the inductor must be zero as the current can not instantly change. Substituting the equation for $$v_c(t)$$ into the equation for the inductor and solving at the instant the switch was closed (t=0) gives: $$ i(t)=\frac{dv_c(t)}{dt}C $$

$$ 0=100\cdot10^{-9}\big[4359B_2-1000B_1 \big] $$ Therefore $$B_2\approx-0.229$$. Once $$v_c(t)$$ is known, the voltage across the inductor and resistor ($$V_{out}$$) is given by: $$ v_{out}=e^{-1000t}\big[\cos(4359t)+0.229\sin(4359t)\big] $$ You have missed a lot of steps, where are they?

Figure 2: Underdamped Resonse File:Example1 underdamped.png

title: Electronics/RCL time domain simple


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Electronics/Inductors

Inductor
An inductor is a passive electronic component dependent on frequency used to store electric energy in the form of a magnetic field. An inductor has the symbol
 * Inductor diagram.svg

Inductance
Inductance is the characteristic of the Inductor to generate a magnetic field for a given current. Inductance has a letter symbol L and measured in units of Henry (H).
 * $$L = \frac{B}{I}$$

This section list formulas for inductances in specific situations. Beware that some of the equations are in Imperial units.

The permeability of free space, μ0, is constant and is defined to be exactly equal to 4π×10-7 H m-1.

Basic inductance formula for a cylindrical coil

 * $$L=\frac{\mu_0\mu_rN^2A}{l}$$
 * L = inductance / H
 * μr = relative permeability of core material
 * N = number of turns
 * A = area of cross-section of the coil / m2
 * l = length of coil / m

The self-inductance of a straight, round wire in free space

L_{self} = \frac{\mu_0 b}{2 \pi} \left[ \ln \left(\frac{b}{a}+\sqrt{1+\frac{b^{2}}{a^{2}}}\right) -\sqrt{1+\frac{a^{2}}{b^{2}}}+\frac{a}{b}+\frac{\mu_{r}}{4} \right] $$

 * Lself = self inductance / H(?)

 * b = wire length /m
 * a = wire radius /m
 * $$\mu_r$$ = relative permeability of wire

If you make the assumption that b >> a and that the wire is nonmagnetic ($$\mu_r=1$$), then this equation can be approximated to

 * $$L_{self} = \frac{\mu_0 b}{2 \pi} \left[ \ln \left( \frac{2b}{a} \right) - 3/4 \right]$$ (for low frequencies)

 * $$L_{self} = \frac{\mu_0 b}{2 \pi} \left[ \ln \left( \frac{2b}{a} \right) - 1 \right]$$ (for high frequencies due to the skin effect)
 * L = inductance / H
 * b = wire length / m
 * a = wire radius / m

The inductance of a straight wire is usually so small that it is neglected in most practical problems. If the problem deals with very high frequencies (f > 20 GHz), the calculation may become necessary. For the rest of this book, we will assume that this self-inductance is negligible.

Inductance of a short air core cylindrical coil in terms of geometric parameters:

 * $$L=\frac{r^2N^2}{9r+10l}$$
 * L = inductance in μH
 * r = outer radius of coil in inches
 * l = length of coil in inches
 * N = number of turns

Multilayer air core coil

 * $$L = \frac{0.8r^2N^2}{6r+9l+10d}$$
 * L = inductance in μH
 * r = mean radius of coil in inches
 * l = physical length of coil winding in inches
 * N = number of turns
 * d = depth of coil in inches (i.e., outer radius minus inner radius)

Flat spiral air core coil

 * $$L=\frac{r^2N^2}{(2r+2.8d) \times 10^5}$$
 * L = inductance / H
 * r = mean radius of coil / m
 * N = number of turns
 * d = depth of coil / m (i.e. outer radius minus inner radius)

Hence a spiral coil with 8 turns at a mean radius of 25 mm and a depth of 10 mm would have an inductance of 5.13µH.

Winding around a toroidal core (circular cross-section)

 * $$L=\mu_0\mu_r\frac{N^2r^2}{D}$$

 * L = inductance / H
 * μr = relative permeability of core material
 * N = number of turns
 * r = radius of coil winding / m
 * D = overall diameter of toroid / m

Quality of good inductor
There are several important properties for an inductor that may need to be considered when choosing one for use in an electronic circuit. The following are the basic properties of a coil inductor. Other factors may be important for other kinds of inductor, but these are outside the scope of this article.

 * Current carrying capacity is determined by wire thickness and resistivity.
 * The quality factor, or Q-factor, describes the energy loss in an inductor due to imperfection in the manufacturing.
 * The inductance of the coil is probably most important, as it is what makes the inductor useful. The inductance is the response of the inductor to a changing current.

The inductance is determined by several factors.

 * Coil shape: short and squat is best
 * Core material
 * The number of turns in the coil. These must be in the same direction, or they will cancel out, and you will have a resistor.
 * Coil diameter. The larger the diameter (core area) the larger the induction.

Coil's Characteristics
For a Coil that has the following dimension
 * [[Image:Basic Inductor with B-field.svg|300px]]
 * Area enclosed by each turn of the coil is A
 * Length of the coil is 'l'
 * Number of turns in the coil is N
 * Permeability of the core is μ. μ is given by the permeability of free space, μ0 multiplied by a factor, the relative permeability, μr
 * The current in the coil is 'i'

The magnetic flux density, B, inside the coil is given by:

 * $$B=\frac{N \mu i}{l}$$

We know that the flux linkage in the coil, λ, is given by;

 * $$\lambda=NBA \,$$

Thus,

 * $$\lambda=\frac{N^2A\mu}{l}i$$

The flux linkage in an inductor is therefore proportional to the current, assuming that A, N, l and μ all stay constant. The constant of proportionality is given the name inductance (measured in Henries) and the symbol L:

 * $$\lambda=Li \,$$

Taking the derivative with respect to time, we get:

 * $$\frac{d \lambda}{dt}=L \frac{di}{dt} + i \frac{dL}{dt}$$

Since L is time-invariant in nearly all cases, we can write:

 * $$\frac{d \lambda}{dt}=L \frac{di}{dt}$$

Now, Faraday's Law of Induction states that:

 * $$-\mathcal{E}=N \frac{d \Phi}{dt}=\frac{d \lambda}{dt}$$

We call $$-\mathcal{E}$$ the electromotive force (emf) of the coil, and this is opposite to the voltage v across the inductor, giving:

 * $$v=L \frac{di}{dt}$$

This means that the voltage across an inductor is equal to the rate of change of the current in the inductor multiplied by a factor, the inductance. note that for a constant current, the voltage is zero, and for an instantaneous change in current, the voltage is infinite (or rather, undefined). This applies only to ideal inductors which do not exist in the real world.

This equation implies that

 * The voltage across an inductor is proportional to the derivative of the current through the inductor.
 * In inductors, voltage leads current.
 * Inductors have a high resistance to high frequencies, and a low resistance to low frequencies. This property allows their use in filtering signals.

An inductor works by opposing current change. Whenever an electron is accelerated, some of the energy that goes into "pushing" that electron goes into the electron's kinetic energy, but much of that energy is stored in the magnetic field. Later when that or some other electron is decelerated (or accelerated the opposite direction), energy is pulled back out of the magnetic field.

Inductor and Direct Current Voltage (DC)
When a coil of several turns is connected to an electricity source in a closed loop, the current in the circuit induces a magnetic field that has the same properties as a Magnetic Field of a Magnet.
 * $$B = L I$$

When the current is turned off, the Magnetic Field does not exist.
 * $$B = 0$$

Conducting Coil is called ElectroMagnet

Inductor's Voltage

 * $$v=L\frac{di}{dt}$$

Inductor's Current

 * $$ i = \frac{1}{L} \int v \cdot dt$$

Reactance

 * $$X_L = \omega L \angle 90 = j \omega L = sL$$, where $$s = j \omega $$.

Impedance

 * $$R_L + X_L = R_L \angle 0 + \omega L \angle 90 = R_L + j \omega L = R_L + sL$$

Angle Difference Between Voltage and Current
For Lossless Inductor
 * The angle difference between Voltage and Current is 90

For Lossy Inductor
 * $$Tan \theta = \omega \frac{L}{R_L} = 2\pi f \frac{L}{R_L} = \frac{2\pi}{t} \frac{L}{R_L}$$

Changing the value of L and RL will change the value of Angle of Difference, Angular Frequency, Frequency and Time.
 * $$\omega = \frac{1}{Tan\Theta} \frac{L}{R_L}$$
 * $$f = \frac{1}{2\pi Tan \Theta} \frac{L}{R_L}$$
 * $$t = \frac{t}{2\pi Tan \Theta} \frac{L}{R_L}$$

Time Constant

 * $$T = \frac{L}{R_L}$$

Quality factor
Quality factor denoted as Q is defined as the ability to store energy to the sum total of all energy losses within the component
 * $$Q = \frac{X}{R}$$

Series Connection

 * [[Image:Inductors in Series.svg]]
 * $$L_{eq}=L_1+L_2+\cdots+L_n$$

Parallel Connection

 * [[Image:Inductors in Parallel.svg]]
 * $$\frac{1}{L_{eq}}=\frac{1}{L_1}+\frac{1}{L_2}+\cdots+\frac{1}{L_n}$$

title: Electronics/Inductors


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Electronics/LR

LR Circuits
An LR circuit has an inductor and a resistor.

When the circuit is turned on the inductor will initially oppose the flow of electrons and no current will flow. Over time the inductor will stop opposing the current and will act as a short allowing current to flow unhindered.

Once the current is shut off the inductor will oppose the decrease in current. This only happens if there is a resistor to bleed off the current.

title: Electronics/LR


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Electronics/RF Basics

Originally people thought that radio waves propagate through the ether.

The ether was disproved by showing that it did not flow.

title: Electronics/RF Basics


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Electronics/Signal Modulation

Modulation and Mixing
Put simply, modulation is the change of an electric signal based on the change in another signal. Another way to look at it practically, is the use of electric signals to carry information.

mixing is the addition and subtraction of signals.

Magic equation: $$cos(x)cos(y) = \frac{cos(x - y) + cos(x + y)}{2}$$ Has strange effects on bandwidth and creates sidebands.

CW (Continuous Wave)

 * morse code

AM (Amplitude Modulation)
simpler than FM. An AM receiver detects the power of the radio wave, and amplifies changes in the power measurement to drive a speaker or earphones.

AM radio. known as medium wave. started in the 1920s. has a long enough wavelength that it diffracts and follows the curvature of the earth traveling a great distance. lower audio fidelity. used for broadcasts. Affected by light and solar flares, and works better during the night. Clear channel stations are allowed to broadcast all the time, but other stations are only allowed to broadcast during the day.

 * Crystal Radio: primitive radio consists of an antenna and a diode and a speaker in parallel.

SSB (Single SideBand)
AM with only one side band. carrier.The other one sideband block or can be use for other information transmission. qadeerhussain99@yahoo.com

FM (Frequency Modulation)
In FM modulation, frequence of carrier signal vairy according to the audio frequency signal(Which is our actual signal).
 * VCO (Voltage Controlled Oscillator): Oscillator that is controlled by voltage.

PM (Phase Modulation)
Change phase by modifying capacitor and inductor values. Since capacitors and inductors are 180 degrees out of phase.

title: Electronics/Signal Modulation


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Electronics/Symbols

Switches
See here for more examples:

Greek characters
One reason people don't understand math or Physics very well is that it literally is Greek to them.

 * alpha α
 * beta β
 * gamma γ
 * delta δ
 * epsilon ε
 * zeta ζ
 * eta η
 * theta θ
 * iota ι
 * kappa κ
 * lambda λ
 * mu μ
 * nu ν
 * xi ξ
 * pi π
 * piv ϖ
 * rho ρ
 * sigma σ
 * sigmaf ς
 * tau τ
 * upsilon υ
 * phi φ
 * chi χ
 * psi ψ
 * omega ω
 * Gamma Γ
 * Delta Δ
 * Theta Θ
 * Lambda Λ
 * Xi Ξ
 * Pi Π
 * Sigma Σ
 * Upsilon Υ
 * Phi Φ
 * Psi Ψ
 * Omega Ω

title: Electronics/Symbols


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Electronics/RCL time domain1

Figure 1: RCL circuit

When the switch is closed, a voltage step is applied to the RCL circuit. Take the time the switch was closed to be 0s such that the voltage before the switch was closed was 0 volts and the voltage after the switch was closed is a voltage V. This is a step function given by $$V\cdot u(t)$$ where V is the magnitude of the step and $$u(t)=1$$ for $$t\geq0$$ and zero otherwise.

To analyse the circuit response using transient analysis, a differential equation which describes the system is formulated. The voltage around the loop is given by:

$$ Vu(t)=v_c(t)+\frac{di(t)}{dt}L+Ri(t) \mbox{ (1)} $$

where $$v_c(t)$$ is the voltage across the capacitor, $$\frac{di(t)}{dt}L$$ is the voltage across the inductor and $$Ri(t)$$ the voltage across the resistor.

Substituting $$i(t)=\frac{dv_c(t)}{dt}C$$ into equation 1:

$$ Vu(t)=v_c(t)+\frac{d^2v_c(t)}{dt^2}LC+R\frac{dv_c(t)}{dt}C $$ $$ \frac{d^2v_c(t)}{dt^2}+\frac{R}{L}\frac{dv_c(t)}{dt}+\frac{1}{LC}v_c(t)=\frac{Vu(t)}{LC} \mbox{ (2)} $$

The voltage $$v_c(t)$$ has two components, a natural response $$v_n(t)$$ and a forced response $$v_f(t)$$ such that:

$$ v_c(t)=v_f(t)+v_n(t)\mbox{ (3)} $$

substituting equation 3 into equation 2.

$$ \bigg[\frac{d^2v_n(t)}{dt^2}+\frac{R}{L}\frac{dv_n(t)}{dt}+\frac{1}{LC}v_n(t)\bigg]+\bigg[\frac{d^2v_f(t)}{dt^2}+\frac{R}{L}\frac{dv_f(t)}{dt}+\frac{1}{LC}v_f(t)\bigg]=0+\frac{Vu(t)}{LC} $$

when $$t>0s$$ then $$u(t)=1$$:

$$ \bigg[\frac{d^2v_n(t)}{dt^2}+\frac{R}{L}\frac{dv_n(t)}{dt}+\frac{1}{LC}v_n(t)\bigg]=0 \mbox{ (4)} $$ $$ \bigg[\frac{d^2v_f(t)}{dt^2}+\frac{R}{L}\frac{dv_f(t)}{dt}+\frac{1}{LC}v_f(t)\bigg]=\frac{V}{LC} \mbox{ (5)} $$

The natural response and forced solution are solved separately.

Solve for $$v_f(t):$$

Since $$\frac{V}{LC}$$ is a polynomial of degree 0, the solution $$v_f(t)$$ must be a constant such that:

$$ v_f(t)=K $$ $$ \frac{dv_f(t)}{dt}=0 $$ $$ \frac{d^2v_f(t)}{dt}=0 $$

Substituting into equation 5:

$$ \frac{1}{LC}K=\frac{V}{LC} $$ $$ K=V $$ $$ v_f=V \mbox{ (6)} $$

Solve for $$v_n(t)$$:

Let: $$ \frac{R}{L}=2\alpha $$ $$ \frac{1}{LC}=\omega_n^2 $$ $$ v_n(t)=Ae^{st} $$

Substituting into equation 4 gives:

$$ \frac{d^2Ae^{st}}{dt^2}+2\alpha\frac{dAe^{st}}{dt}+\omega_n^2Ae^{st}=0 $$ $$ s^2Ae^{st}+2\alpha Ae^{st}+\omega_2^2Ae^{st}=0 $$ $$ s^2+2\alpha s+\omega_n^2=0 $$

$$ s=\frac{-2\alpha\pm\sqrt{4\alpha^2-4\omega_n^2}}{2}=-\alpha\pm\sqrt{\alpha^2-\omega_n^2} $$

Therefore $$v_n(t)$$ has two solutions $$Ae^{s_1t}$$ and $$Ae^{s_2t}$$

where $$s_1$$ and $$s_2$$ are given by:

$$ s_1=-\alpha+\sqrt{\alpha^2-\omega_n^2} $$ $$ s_2=-\alpha-\sqrt{\alpha^2-\omega_n^2} $$

The general solution is then given by:

$$ v_n(t)=A_1e^{s_1t}+A_2e^{s_2t} $$

Depending on the values of the Resistor, inductor or capacitor the solution has three posibilies.

1. If $$\alpha > \omega_n$$ the system is said to be overdamped. The system has two distinct real solutions: $$ v_n(t)=A_1e^{\big(-\alpha+\sqrt{\alpha^2-\omega_n^2}\big)t}+A_2e^{\big(-\alpha-\sqrt{\alpha^2-\omega_n^2}\big)t} $$ 2. If $$\alpha = \omega_n$$ the system is said to be critically damped. The system has one real solution: $$ v_n(t)=\big(A_1+A_2\big)\big(e^{-\alpha t}\big) $$
 * Let $$B_1=A_1+A_2$$:

$$ v_n(t)=Be^{-\alpha t} $$

3. If $$\alpha < \omega_n$$ the system is said to be underdamped. The system has two complex solutions: $$ s_1=-\alpha+j\sqrt{\omega_n^2-\alpha^2} $$ $$ s_2=-\alpha-j\sqrt{\omega_n^2-\alpha^2} $$

$$ v_n(t)=e^{-\alpha t}\Big[A_1e^{j\sqrt{\omega_n^2-\alpha^2}t}+A_2e^{-j\sqrt{\omega_n^2-\alpha^2}t}\Big] $$
 * By Euler's formula ($$e^{j\phi}=\cos{\phi}+j\sin{\phi}$$):

$$ v_n(t)=e^{-\alpha t}\big[(A_1+A_2)\cos(\sqrt{\omega_n^2-\alpha^2} t)+j(-A_1+A_2)\sin(\sqrt{\omega_n^2-\alpha^2} t)\big] $$

 * Let $$B=A_1+A_2$$ and $$B_2=j(-A_1+A_2)$$

$$ v_n(t)=e^{-\alpha t}\big[B_1\cos(\sqrt{\omega_n^2-\alpha^2} t)+B_2\sin(\sqrt{\omega_n^2-\alpha^2} t)\big] $$

title: Electronics/RCL time domain1


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Electronics/RCL time domain2

Figure 1: RCL circuit

Example
Given the following values what is the response of the system when the switch is closed?

$$ \alpha=\frac{R}{2L}=1000 $$ $$ \omega_n=\frac{1}{\sqrt{LC}}\approx 4472 $$

$$ v_n(t)=e^{-1000t}\big[B_1\cos(4359t)+B_2\sin(4359t)\big] $$

Solve for $$B_1$$ and $$B_2$$:

From equation \ref{eq:vf}, $$v_f=1$$ for a unit step of magnitude 1V. Therefore substitution of $$v_f$$ and $$v_n(t)$$ into equation \ref{eq:nonhomogeneous} gives:

$$ v_c(t)=1+e^{-1000t}\big[B_1\cos(4359t)+B_2\sin(4359t)\big] $$

for $$t=0$$ the voltage across the capacitor is zero, $$v_c(t)=0$$

$$ 0=1+B_1\cos(0)+B_2\sin(0) $$ $$ B_1=-1\mbox{ (7)} $$

for $$t=0$$, the current in the inductor must be zero, $$i(0)=0$$

$$ i(t)=\frac{dv_c(t)}{dt}C $$ $$ i(0)=100\cdot10^{-9}\big[e^{-1000t}\big(-4359B_1\sin(4359t)+4359B_2\cos(4359t)\big)-1000e^{-1000t}\big(B_1\cos(4359t)+B_2\sin(4359t)\big)\big] $$ $$ 0=100\cdot10^{-9}\big[4359B_2-1000B_1 \big] $$

substituting $$B_1$$ from equation \ref{eq:B1} gives

$$ B_2\approx-0.229 $$

For $$t>0$$, $$v_c(t)$$ is given by:

$$ v_c(t)=1-e^{-1000t}\big[\cos(4359t)+0.229\sin(4359t)\big] $$

$$v_{out}$$ is given by:

$$ v_{out}=V_{in}-v_c(t) $$ $$ v_{out}=Vu(t)-v_c(t) $$

For $$t>0$$, $$v_{out}$$ is given by:

$$ v_{out}=e^{-1000t}\big[\cos(4359t)+0.229\sin(4359t)\big] $$

title: Electronics/RCL time domain2


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Electronics/Signal Propagation

Generation
AC source alternates on a piece of wire. This creates an electric field that creates a magnetic field that creates an electric field. These waves are known as Electro-Magnetic waves, and are photons that travel through free space.

 * EMP (Electro-Magnetic Pulse): Generated by a nuclear blast, a high intensity blast of many frequencies. Shorts out electrical components.

Propagation
Originally people thought that photons propagate through an aether wind. The aether was disproved by showing that it was not flowing from any direction even though the earth is moving.

''My first tie in with other books. The idea is to have a short intro which motivates the other books so people will be interested in reading them. ''

In showing that the aether did not exist came the realization that light travels at the same speed regardless of how fast you are moving and that time is relative and events do not happen at the same time. With that knowledge came the famous E=MC2 equation, time travel, the secrets behind blackholes, and how gravity and energy warp time and space. Click Here to unlock these secrets of the universe.

Antennas
You only need a quarter wavelength antenna to resolve a full wavelength. It is hard to resolve wavelengths of 200 meters. Use powerlines. Fractal antennas allow to compress the antenna size. As long as the antenna is long enough for a standing wave it does not matter how it is compressed.

 * aerials

Range
The earth behaves like a conductor. The ionosphere also behaves like a conductor. Both can reflect radio waves.

title: Electronics/Signal Propagation


text:
Template talk:High School Mathematics Extensions/Matrices

The multiplication section is unclear... r3m0t (cont) (talk) 10:07, 27 Mar 2004 (UTC)

What is δ? r3m0t (cont) (talk) 10:00, 15 Apr 2004 (UTC)

 * The Kronecker delta. The definition there is what the function is, however, and that's about it... Dysprosia 10:09, 15 Apr 2004 (UTC)
 * It's the Greek letter, delta.

 * Considering I wrote &delta; in the source code, I already knew that ;) r3m0t (cont) (talk) 11:09, 16 Apr 2004 (UTC)

If a variable is a matrix, is it always capitalised? Is it always italicised? r3m0t (cont) (talk) 11:36, 15 Apr 2004 (UTC)

 * When you write on paper, capitalize it. When it's printed, I think convention is to have capitals, bold, but not italicize. Dysprosia 12:15, 15 Apr 2004 (UTC)

I thought that one of the important things about multiplication is that it is commutative i.e. $$ab = ba$$ but it seems that with matrices this is not so. Why is this definition of multiplying matrices more useful than an alternative, commutative one? r3m0t (cont) (talk) 11:43, 15 Apr 2004 (UTC)

 * No, matrix multiplication is noncommutative. AB != BA. It stems from the definition of matrices representing systems of equations, and is a bit complex to quickly explain here. If you like, pick two matrices, multiply them in the "two-finger" method (not sure if this nifty method is explained here), and then change the order. You might not get the same answer. Dysprosia 12:15, 15 Apr 2004 (UTC)

 * As for why we use that definition, being noncommutative is very useful. It happens a lot in real problems. E.g rotate a book 90 degrees round a vertical axis then 90 degrees round an horizontal axis and it'll end up differently orientated to if you spin it roun the horizontal axis before the vertical. When you rotate things, order matters, so rotation is not commutative. We need non-commutating matrices to describe it, and many other physically interesting systems. Carandol

 * Or that a matrix represents a linear transformation, and that performing one transform before another is not necessarily the same as doing it in the other order. Dysprosia 12:39, 15 Apr 2004 (UTC)

problem with exercises
I have found a problem with exercise 4 in the exercises section after the text about multiplication of diagonal matrices. It seems to me that the multiplication of the two matrices should be reversed eg instead of c*b what is is now, it should be b*c. Otherwise this equation isn't usefull for the e and f part of the exercise.

The A defined in the equation in the d part of the exercise isn't the same A as defined in the a part of the exercise, as you can see below:

\begin{pmatrix} 3&1\\ 1&1\\ \end{pmatrix} \begin{pmatrix} 3&0\\ 0&1\\ \end{pmatrix} \begin{pmatrix} \frac{1}{2}&-\frac{1}{2}\\ -\frac{1}{2}&\frac{3}{2}\\ \end{pmatrix} = \begin{pmatrix} 4&-3\\ 1&0\\ \end{pmatrix} $$ Mmartin 21:33, 13 Aug 2004 (UTC)

 * My mistake, thanks for pointing it out. It's been fixed Xiaodai 14:25, 14 Aug 2004 (UTC)

Update to consistency
Need to change the vectors to have arrows on them, just to be consistency. This is a reminder that i should do that. Xiaodai 12:48, 30 Jan 2005 (UTC)

Cofactor Expansion
Shouldn't you talk about cofactor expansion for finding the determinant of a matrix? Giving only the formula for a 2x2 matrix won't take readers very far. At the very least, give them the general method to find determinants using permutations.


text:
User talk:Delta G~enwikibooks

Excuse me, but you are not supposed to modify my user page. :-) Traroth 13:36, 27 Mar 2004 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Delta G. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Delta G~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:09, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 04:52, 19 April 2015 (UTC)

title: User talk:Delta G~enwikibooks


text:
Authoring Webpages/Creating a simple page

= Creating a simple webpage =

Time to get our hands dirty! (In a manner of speaking.)

Text structures
In the first chapter, which stated the requirements for following this course, a small exercise was printed, in which you created your first simple web page. If you haven't done that exercise yet, go there now and do it.

Text entered into a text editor and saved to a hard disk, or other form of storage, is often called a "plain text file". Plain text files generally provide three small ways for separating text. Tabs and spaces are used for separating words and returns are used for separating paragraphs.

People have found creative ways of producing intricate layouts using just these small methods of markup. In web pages, however, this method of laying out text doesn't work. A web browser will collapse all consecutive spaces, tab stops and returns into one single space or soft return, depending on where on the line the word occurs. HTML does layout a much different way, which will be discussed later.

When you structure a text, you generally do so to make it easier to digest and to read. By making chapter and section headings more pronounced, you allow the reader to skim over a text until they find an especially interesting part. By using introductions and abstracts, you allow a reader to decide if this text will be interesting to them. You can use illustrations, because sometimes people will much sooner understand what's going on when they can see what's going on.

HTML, the HyperText Markup Language for the web, and its successor XHTML, the eXtensible HyperText Markup Language, allow you to impose a structure on a plain text document. It replaces the few simple mark-up methods plain text allows you by its own. (Note: XHTML has been superceded by HTML5.)

The way HTML lets you do all this, is by letting you label certain parts of the text as a heading, a paragraph, an image, a table, a list, etc. Some structures are not supported by HTML, since it is a relatively simple markup language. For instance, there is no element for introductions or leads. The reader will have to infer from the position in a text which is the introduction, the lead or the abstract.

Each part of an HTML document is called an element. Elements are separated from each other by a type of label called tags.

An example:

This is an important example.

What you see above is a paragraph element with an embedded emphasis element. The paragraph element starts with a
 tag and ends with a
 tag. The emphasis element starts with an  tag and ends with an  tag.

A web page by any other name...
There are several versions of the HTML standard. The most current is HTML5. However, web browsers should also support older versions of the standard, so that examples such as the one given in the Requirements chapter are considered valid HTML documents.

Every web page must have a  element (under older versions of HTML this was the only required element):

<title>My webpage</title>

The title is the text by which the browser window will be named. It is the text that appears at the top of your browser window, and it is the default name of the bookmark (or favorite) used by the browser. It is also the title by which the page will be listed by a search engine.

Find a descriptive title. The heading of your page will often do just fine. The heading of this chapter is "Creating a simple web page", so its title could be the same text. Since this web page explains to you how to create a simple web page, that would be an excellent title.

Bad titles abound on the web. For example, a company might name their page

<title>Big Fridge Manufacturer Inc.</title>

If you are lucky, they will even add in a bit of information related to the web page you are visiting, for instance:

<title>Big Fridge Manufacturer Inc. - Manual of the Cool 3000 ice box</title>

Better for the visitor is:

<title>Manual of the Cool 3000 ice box - Big Fridge Manufacturer Inc.</title>

After all, it is much more likely that the visitor who gets to this page is searching for the manual, rather than for company info.

So, the lesson is: always put the important information first. Often, you only have a limited amount of characters available to you in your bookmarks menu, in the search engine listing or in the window title bar; utilize that space to the maximum.

An HTML document with only a title element is not very useful. We will now introduce you to a couple of elements that will allow you to make good use of 90% of the power of the web.

A simple linking webpage

 * title
 * The name of a page.

 * h1
 * The most important heading(s) on a page, often the same as the title.

 * h2
 * A sub-heading.

 * p
 * A paragraph.

 * a
 * A link.

With these elements, we can make the following simple web page:

Exercise 2-1
Copy the above sample code to your text editor. Save it as exercise2-1.html. Open it in a web browser. Does it display like you expected?

Answers
For answers, see Answers to Questions and Exercises.

Creating a link
The  tags in the previous example have a special purpose. They create anchors. (Anchors are more commonly referred to as "links".) They contain attributes with attached values. Attributes are part of a tag that give the browser additional information about the element. Each attribute is followed by an equals sign (=) and a value in quotation marks (").

tags have several possible attributes. The most important are  and. is the attribute that defines the URL (Uniform Resource Locater) or URI (Uniform Resource Indicator) (more commonly known as an "address"). This is the destination that the link leads to: another document, or a location within the same document. Commonly, addresses are called URLs; however, this practice has become deprecated, and it is now recommended that you use the broader term "URI", instead.

The  is a unique name for the link, which can be used by other links to refer to it.

(Note: Previous versions of HTML used  instead of  .)

URIs typically have the following form:

For example

The protocol for web pages is usually  (HyperText Transfer Protocol) or its secure variant. In this example, the link would take you to the  section of the   document on the   domain, using.

Note, however, that most parts of this are optional, depending upon how you want to use the URI. URIs can be relative or absolute. An absolute URI will include the domain as part of the address. (The  part.)

An  can just be a relative path (for example  ): in that case, the address will be calculated from the page that contains the link.

An  can also just be a domain name:   leads to a website with that address; the web server of that site is supposed to figure out which document you want. This typically defaults to  or.

Elements deconstructed
An HTML document consists of elements. These elements are constructed as follows:

An opening tag may contain attributes. Attributes often have values.

The tag that closes an element is just like the opening tag, but has a slash in front of the name, and cannot contain attributes:

Some elements cannot contain other elements. The HTML standard defines which elements can be contained by an element. The permitted combinations vary from version to version.

Elements are either block-level elements or inline elements. With block-level elements, the browser sets off the element in its own "block". It has a return placed both before and after it. Some examples of this are headings (, ,  , and so on), paragraphs , and list items. Inline elements are not treated this way, so (for example) they can be inserted into paragraphs without disrupting the flow of the paragraph. Good examples of this are anchors, emphasis , and images.

Block-level elements can contain inline elements, but inline elements cannot contain block-level elements.

For instance, the following is valid HTML:

But this is not:

, then  will link to it. That means that when you activate the link, the web page will be displayed starting at the anchor (rather than as usual from the top).

Make a copy of the web page you created in Exercise 2-1 and save it as. Change this file to include a 'menu' of anchors at the top that link to the headings of the different subsections (Family, Friends).

Exercise 2-4
There is a hybrid form of book and game called Choose Your Own Adventure (CYOA). In such a game-book, you read a bit of text as in a normal book, but after a while, you get to make a choice as to how to continue.

For instance:

You are sitting in the tub, soaking and relaxing. Your rubber ducky is chattering away happily when suddenly a pike grabs it from below and drags it down.

- If you dive into to the water to save the ducky, go to page 89

- If you pull the plug to empty the bath, go to page 24

In this exercise, you will write a short CYOA, in which the choices are represented by anchors that will lead to the text continuing from that choice. Every "chapter" must be a separate web page.

Keep it snappy and don't spend too much time on this. Ten to twenty web pages should be sufficient. The story does not need to be good or finished.

Tip: Create a template HTML file which you can use to base all subsequent chapters.

Exercise 2-5
Create a web page and save it as "exercise2-5.html". The web page should contain a short, informative text about a subject of your choice. It should contain at least three working links to external websites about the subject.

Answers
For answers, see Answers to Questions and Exercises.

Images
Including an image on a webpage is done using the  element. is one of a class of elements referred to as "self-closing". Self-closing elements don't have a closing tag. Instead, they end with. (In HTML5, the slash is optional; however, it is considered a best practice to include it.)

The  element has two obligatory attributes:   and.

takes a URI as its value. In this case, the URI will be the "address" (location) of the image.

Since URIs can be relative, if the image is located in the same folder as the web page that includes it, the URI can consist merely of the file name of the image. More commonly, the image will be located with other images in a directory called. It is a good practice to keep your images in a separate directory, because it will make your site better organized.

The  attribute contains a textual description that appears when the image cannot be displayed. For instance, if the image is a photo of a lake with a castle, you could have the following code:

When the purpose of the image is decorative, you might want to use an empty alt value. That way, when the page is displayed, the "decorative" text will not interrupt the flow of the page's main text.

However, when the image has a function to fulfill on a webpage, the presence of alt text is very important for visitors who can't see the image. For instance, many webpages have navigation built from menus of links, where the links are represented by images. If the images can't be displayed and there's no alt text, users won't be able to use the navigation.

The  element lets you embed an image on a page. You can of course also link to an image that you do not want to display on the page, because it has no role there. For instance, if you want to offer people the chance to download photos you made, you can offer links to those photos. For that you use the same  element that we have been using to link to other webpages:

Note how you can create links to every file that can be located using a URL. By indicating that a photo is stored in the JPEG format (a very common file format for photos) and by indicating the file size, we give visitors the opportunity to decide whether they A) can use a file of this format and B) whether they are willing to download a file of this size.

Pre-formatted text
HTML contains many more elements (for example, HTML 4.01, contains 91 different elements), but for now we will discuss only one more before moving on to the style of web-writing.

The  element allows you to retain plain text formatting (as discussed shortly at the beginning of this chapter). This means that within the element, consecutive spaces, tabs and hard returns will not be collapsed into a single space or soft return.

There is little use for this element. It stops the text from reflowing neatly when the browser width is reduced or expanded, causing visitors to scroll horizontally, which web-surfers generally hate to do. HTML and its companion layout language CSS have plenty of options to display line-breaks and indentation. Also, it is pretty meaningless in non-visual browsers.

However, when you wish to copy pre-formatted text from other documents, it may be handy to use the  element until you have the time to mark that text up.

Example:

1 2    4        8

More exercises
The following exercises are optional. You can use them to practice putting images on your webpages.

Exercise 2-6
Download the following images, and put them all on a webpage that you will save as 'exercise2-6.html'. Think of useful  texts.

To download linked files, a lot of browsers contain a Save Link As function. In graphical browsers using a mouse, this function is often part of the context menu. On the PC this means you have to click you right mouse button, on Mac OS this means you have to press the -key and press the mouse button.

(images to follow later)

Answers
For answers, see Answers to Questions and Exercises.


text:
Talk:Applicable Mathematics/Probability

"Another example of a random experiment and outcome is the birth of a child." What is random about that?

"When you throw a die, you can get 1, 2, 3, 4, 5 or 6 eyes. These are the possible outcomes in a throw." I often throw a die that lands diagonally against the edge of an object, causing an unwanted result. Is there a name for such results? How do you determine what's part of the sample space and what not? I can imagine that this is a matter of much contention in statistical analysis: what the one calls a valid result, the other denies.--Branko 17:31, 27 Mar 2004 (UTC) "I think that you have to state the number of completed trials. If a die lodges itself somewhere it simply anincomplete trial and shouldn't be included in the results,unless you want to report incomplete trials for others to consider" [[User:Druid] 14:29, 30 Sept.2007

title: Talk:Applicable Mathematics/Probability


text:
Electronics/RCL frequency domain

Figure 1: RCL circuit

Define the pole frequency $$\omega_n$$ and the dampening factor $$\alpha$$ as:

$$ \frac{R}{L}=2\alpha $$ $$ \frac{1}{LC}=\omega_n^2 $$

To analyze the circuit first calculate the transfer function in the s-domain H(s). For the RCL circuit in figure 1 this gives: $$ H(s)=\frac{s\big(s+2\alpha\big)}{s^2+2\alpha s+\omega_n^2} $$ $$ H(s)=\frac{s\big(s+2\alpha\big)}{\big(s+\alpha+j\sqrt{\omega_n^2-\alpha^2}\big)\big(s+\alpha-j\sqrt{\omega_n^2-\alpha^2}\big)} $$

When the switch is closed, this applies a step waveform to the RCL circuit. The step is given by $$Vu(t)$$. Where V is the voltage of the step and u(t) the unit step function. The response of the circuit is given by the convolution of the impulse response h(t) and the step function $$Vu(t)$$. Therefore the output is given by multiplication in the s-domain H(s)U(s), where $$U(s)=V\frac{1}{s}$$ is given by the Laplace Transform available in the appendix.

The convolution of u(t) and h(t) is given by: $$ H(s)U(s)=\frac{V\big(s+2\alpha\big)}{\big(s+\alpha+j\sqrt{\omega_n^2-\alpha^2}\big)\big(s+\alpha-j\sqrt{\omega_n^2-\alpha^2}\big)} $$

Depending on the values of $$\alpha$$ and $$\omega_n$$ the system can be characterized as:

3. If $$\alpha < \omega_n$$ the system is said to be underdamped The solution for h(t)*u(t) is given by: $$ h(t)*u(t)=Ve^{-\alpha t}\big(\cos(\sqrt{\omega_n^2-\alpha^2}t)+\frac{\alpha}{\sqrt{\omega_n^2-\alpha^2}}\sin(\sqrt{\omega_n^2-\alpha^2}t)\big) $$

Example
Given the following values what is the response of the system when the switch is closed?

First calculate the values of $$\alpha$$ and $$\omega_n$$: $$ \alpha=\frac{R}{2L}=1000 $$ $$ \omega_n=\frac{1}{\sqrt{LC}}\approx 4472 $$

From these values note that $$\alpha < \omega_n$$. The system is therefore underdamped. The equation for the voltage across the capacitor is then: $$ h(t)*u(t)=e^{-1000 t}\big(\cos(4359 t)+0.229\sin(4359t)\big) $$

Figure 2: Underdamped Resonse

title: Electronics/RCL frequency domain


text:
User:Juxho~enwikibooks

I work mostly on Consumerium and English Wikipedia and occasionally on Wiktionary and Finnish Wikipedia.

I'm interested in developing Cookbook and UNIX tutorials and Books to Finnish language which is my native tongue.

title: User:Juxho~enwikibooks


text:
Talk:German/Level I/Wie heißt du

Various Topics
In this lesson, it says that "Mein Name ist ..." would be considered incorrect. Er ... um ... no. It's correct. It's slightly less common, and a little more formal than "Ich heiße ..."

I just started reading through the questions and answers, but when I got to the Wie Geht's section problems, a question asks for the word for terrific, which was previously given as Klasse!, but when referring to the answers, it uses Toll!. I think that either Toll! should be added to the lists of responses or the answer to the question should become Klasse! .

Need a guide to pronunciation - how does the esset sound? Is there some phoenetic guidance that can possibly be written down? Any way of including WAV or other audio files to cover the basic pronunciations?
 * I added a link to the pronunciation guide, which has a pretty good overview of the pronunciations of all letters. I can't do audio, but others on the site can. - SamE 05:01, 28 Mar 2004 (UTC)

 * The es-szet sounds no different than the ess-ess. It has another "purpose" (see link to pronunciation guide) - Marsh 20:42, 31 Mar 2004 (UTC)

SamE - Is there a reason for having a Lesson Overview that so closely matches the page TOC? - Marsh 20:42, 31 Mar 2004 (UTC)
 * It works when there isn't a table of contents; you can delete the one on lesson 1 if you want. It also can be a "plan" for the page before I get the page up and running. - SamE 22:00, 31 Mar 2004 (UTC)

 * That makes sense. The TOC "appears" once you have a certain number of header lines on a page. But the "plan" idea sounds good as a development tool. - Marsh 17:06, 2 Apr 2004 (UTC)

Corrected two Anglicism: 'So so' and 'Später' -> 'Ganz gut' and 'Bis später'.
 * You don't need to tell us what you've done. We can see it in the Page history or Recent Changes.
 * Log in so you can edit pages with a username. - SamE 17:34, 7 Apr 2004 (UTC)
 * I suspect the earlier entries may have been Floflei6 before he got his nom de plume. For information: explain on talk pages only when you want to emphasize why a possibly controversial change was made or propose a major change and want consensus. - Marsh 17:47, 7 Apr 2004 (UTC)

I'm just curious, when you list the pronouns you put du and Sie together, which is true, but when you list the conjugations you don't make Sie clear. To me this might suggest that Sie would fit in with the conjugations of du rather then those of sie.. --Alexbl 02:17, 29 May 2004 (UTC)
 * I had that in the note below the blue table, but I guess it wasn't that clear. I tried to fix that just now. - SamE 03:34, 29 May 2004 (UTC)

This lesson is pretty much locked down. Please don't make any big changes (i.e. new sections, deleting/rewriting entire sections, etc.) without consulting this page first. - SamE 19:00, 29 May 2004 (UTC)

The names section, with "our,their,hers his its" does not mention that these are english possesive pronouns. it seems to me there are no possesive pronouns in german. whatever the case may be, some mention of this needs to go on the page. Hfastedge 19:45, 15 Jun 2004 (UTC)
 * This was just an attempt to explain something the long way without actually introducing conjugations until the "Verbs" section. I added a couple comments to clarify it. Please tell me if you can think of another way to do this. Thanks for reading the lesson and helping us out. - SamE 02:47, 16 Jun 2004 (UTC)

Is it Tschüss, or Tschüs? I have a 1993 dictionary and a 2000 textbook, and both say it only has one 's'. - SamE 20:35, 29 Jun 2004 (UTC)
 * it's Tschüss --Moolsan 22:04, 29 Jun 2004 (UTC)
 * Actually, since it is informal language, either Tschüs, Tschüss or Tschüß may be used and found. This is a bit weird, since the word is almost exclusively used in talk, not in the writing. Endymi0n 04:33, 11 November 2005 (UTC)

"Tschau, Susi!"

---> nonsense. Tschau is a "Verballhornung" of Ciao(it.).

This is not German. Susi is no common German name, it is a reduction of Susanne.

Regional other prases are used:

"Tschüss" (Hamburg) ("adjüst" (Helgoland), "Ade", adieu(fr.))

 * There isn't much else that is used as an informal good-bye, so if you have any other better suggestions, please put them here. - SamE 03:06, 1 Sep 2004 (UTC)

 * Right. As stated above this is weird, because there is no such word as "bye" which is used in both talk and writing. "Hi"/"Hallo" for greeting and "Tschau" (ciao)/"Tschüs" for goodbye are quite common, but there is a tendence to use regional words as "Moin" and "Grüß Gott". However, these clearly indicate you as coming from a certain part of Germany (Austria,Switzerland) when mentioned in the wrong part. The statement beneath correctly mentions the use of the phrase "Mach's gut" as a common indirect way to say goodbye. May be added... Endymi0n 04:33, 11 November 2005 (UTC)

 * informal hellos and good-byes are very different, corresponding with the dialects. I would never use one of the above, but Servus or Pfüadi, but this is not for a first chapter. A phrase i heared nearly in every circumstances is "Machs gut!" or "Machen Sies gut!", which is only used when people are frendly (no matter weather they use Sie or Du).

 * It is important instead to add parts like Servus/Grüßgott - we had exchange studendts and I am from Regensburg, Germany. When they came they expected people to say "Guten Morgen!" and friends to say "Tschüß!", but this did not happen. People there simply doesn't use this forms. So they should be added and explained in a note. This will help students when they come to Germany/Austria to understand immediately what people said. Of course one should not add dialect there, but only these few very important words. Maybe even the others like Ade etc. should be added in the note. --SabineCretella 08:22, 14 Mar 2005 (UTC)

somewhere it is mentioned 'das mädchen' but i think it should be 'die mädchen', if im wrong, plz tell me, lest i continue learning wrong Nikhil bandale, email id:nbandale@yahoo.co.in learnin deutsch all the way

 * Mädchen ends in -chen, then it's a very good guess to assume das. And yes, it is das Mädchen. (remember, capital M :) Mike 18:22, 29 Mar 2005 (UTC)

 * "das Mädchen" is actually right. Sounds weird as it is referring to a feminine person, but the neutral aspect refers to the miniaturisation "-chen". Endymi0n 04:33, 11 November 2005 (UTC)

I am german an just read the first lessons. You did it really fine; nobody can believe, that every thing is explained in the first lesson! Learn step by step! It's true, that "Tschau" is a german version from "ciao", but only if you know eachother well and feel good. "Tschüß" is the origin form, sice 2002 we have to write double s, one s can't be correct, you always pronounce it with double ss. The ß is also pronounced. 60 years ago, the german knew thre forms to write s, I think it was first a cause of "good looking and easy writing" (with hand). There existe no Institution in germany for correct writing and til 19th century everybody could write as he liked. The german language includes many other languages and also some grammar of other languages. So meanwhile it's correct to say "Mein Name ist...". Every word with "~chen" or "~lein" means little and get the Artikel "das". In former times houses and farmes had female workers called "die Magd", a little one is "das Mädchen" and now common for every female child; the older words "die Göre" or "die Dirn" (in lower Saxonie "die Deern")changed their meaning: Göre is a cheeky girl and Dirne someone who sells sex. In Southgermany you can use "Das Madel". Be sure, german girls don't like to be "das"!

Pronunciation?
Hi! Thanks to everyone involved in the project. It is a very good guide for beginners but it is really handicapped by the lack of pronunciation for words. I think audio files for the conversations would really do a world of good to the project. I did not know Ich was pronounced as Ish and instead read it as Ikh. Thanks anyway.

 * On my way of doing so... =) BTW: Both pronounciations are wrong, there is no adequate reference in English vocals. Try to pronounce "ch" as a "sh" but touch your palatine not with the tip, but with the middle of your tongue. Endymi0n 04:33, 11 November 2005 (UTC)

I think "Ich" can be pronounced in either way; it seems to be a north/south dialect difference. I've seen pronounciation guides all over the internet and one of the things many of them seem to stress is that the "ch" can be pronounced either "sh" or "kh" and still be correct.

Also, I would like to help with making audiofiles for pronouncing the words, but wikipedia says it prefers this "OGG" format that I've never heard of and I can't find any software that supports saving audio in it. Can someone tell me what it can be made in? Would it really matter too much if I submit it in MP3? --Shdwninja8 21:14, 30 May 2005 (UTC)

 * "[kh]" (with a very soft "k" if pronounced at all) is always the right way to say "ch". Everything else is a regional dialect.
 * MP3 is afaik a patented. [Vorbis.com] provides tools for the free OGG format.
 * --Messi 23:10, 30 May 2005 (UTC)

sorry, but this is not true. the pronounciation "ikh" is only used specific dialekt. The normal "high german" pronounciation just has no english equivalent or similiarity... The sound for the "ch" part of the word is produced by having your tounge loosley in your mouth (without touching your teeth or anything inside your mouth) and use a small amount of air with the right speed

 * Well here's an easy way to get the idea: It's just like the ch in Michigan or Chicago. The usual English ch (change, charge, China) is pronounced tch, remove the t/d and it's exactly right (well, not exactly, it's still more like "sch"). 87.78.124.167 22:48, 29 December 2006 (UTC)

The boy throws the sphere
I think using "die Kugel" as German translation for "ball" is just wrong; the appropriate word would be "der Ball". In some situations, "Kugel" is best translated as "ball", but in most cases, the meaning is more "technical", more "sphere" than "ball". "Kugel" definitely doesn't remind me of anything that is usually thrown by boys.

"Der Junge spielt der Ball" is incorrect, it should be "den Ball" (cases)

 * This is literally translated as "The boy plays the ball" which is nonsense. Correct tranlation is "Der Junge spielt mit dem Ball" (boy plays with the ball) or "Der Junge spielt Ball" which means the boy playing a ball game.

einen?
What is this article einen? as in the sentence "Der Mann hat einen Hut." (I am a beginner.) -- Taku 05:37, 27 Jun 2005 (UTC)

 * Take a look at German: Lesson 3 (Indefinite Articles). einen is indefinite article ein (masculine) in accusative case.

 * Thanks! -- Taku

A bit of cleanup
Now that I'm back, I'm afraid I don't agree with many of the changes that have been made. Over the next few edits, I'm making some major changes to each section. If anyone has a problem with or a question about this, please tell me right here. - SamE 16:33, 12 July 2005 (UTC)

If in doubt...
...about anything, please contact me under endymi0n at trojasonic dot com. I'm native speaker (born and raised in Germany) and my mother teaches German for foreigners. I also did the German Alphabet recording, so if you like it, stroke my soul - I could make some more... =) Greetz, Endymi0n 04:33, 11 November 2005 (UTC)

on questions of format in forming questions
Hey! I am really having a good time using the lessons and am learning quite a lot, but I simply wanted to say that on the section on forming questions it's not very linear. For instance, in the first two paragraphs there should be a consistent phrase instead of using different phrases throughout the paragraphs. However, if the intent is to continue using the different phrases, there should be a break in the text or label it is an example. Just a thought. 72.144.98.126 05:05, 4 January 2006 (UTC)

? Incorrect form in 2nd Conversation
I am questioning the form used for asking the other persons name in this conversation. Is Herr Schwarz older than Franz, or have they met previously? If not, then using "Wie heisst du?" is incorrect, it should be "Wie heissen Sie?", since Sie is proindicated for use where both parties are adult (unless they have agreed to use du), or formal siuations where neither party has met the other, and should be used until they are familiar enough to use du.

Ca you clarify how this situation / conversation formed, and the forms used to support the text? Tmalmjursson 13:05, 11 February 2006 (UTC) Thor's pet yack

 * To me, a native speaker, the dialogue sounds like Herr Schwarz is older than Franz, as you said. I assume Franz is meant to be a child, because only then you get a situation in which one uses "du" while the other uses "Sie". Epsilon 18:11, 9 March 2006 (UTC)

 * I wouldn't worry about the formal forms. I wouldn't use "du" to address a total stranger, a teacher, business man and so on, but no one's gonna kill you if you do. After all they'll be able to tell from your accent that you're not a native and will be positively surprised. It's not like in some Asian cultures where you "lose your face" when you use the wrong honorific. I'm not saying that the rules are wrong, but don't be afraid to commit a faux pas, where not nearly as strict as we're said to be. Same goes for the greeting: No one will be offended when you say "Hi!", although it's probably uncommon for anyone over 30 ;-)

SZ?
I disagree with the statement "upper case ß is written as 'SZ'". I've never ever seen it.

For one thing, ß never is the first letter of a word, so in everyday wiritng it doesn't need to be capitalized. If you want to capitalize a whole word, you'd use SS (Süßigkeiten --> SÜSSIGKEITEN).

Any different views? Epsilon 18:17, 9 March 2006 (UTC)

 * I agree that you will rarely see it even though this sould not have been the case. See here for clarification. Thus it should now be changed to SS in the article. However, I would still continue to use MASZE for Maße, MASSE for Masse to make it easier to understand. Regards --217.83.69.74 19:40, 12 March 2006 (UTC)

Among others, the East German Duden apparently once made an attempt to introduce an upper case "ß" many years ago, but until this day such a glyph is not being used. Up until the spelling reform, Both SZ and SS were correct, when spelling a word in capitals only, such as in "DAS GROSSE/GROSZE HAUS". Note that "GROßE" never has been correct, even if it is often seen, e.g. in publicity. Today, only SS is correct. However, in professional context (I'm an architect) I still prefer the "wrong" SZ, to avoid the aforementioned confusion between "Maße" / "Masse", as both words are quite common there Thamane 20:39, 3 April 2006 (UTC)

Note, that there is also a large ß. Since 2008 the large ß has even it own unicode. More information in German: http://de.wikipedia.org/wiki/Gro%C3%9Fes_%C3%9F 85.179.37.72 (discuss) 22:44, 6 February 2011 (UTC)

Alphabet
The order you are using in the alphabet table is quite unfamiliar to a German native speaker. We just take that direction: abcdefghijklmnopqrstuvwxyz äöüß, not mixing umlauts into usual alphabet HolgiDE 10:49, 21 Mar 2006 (UTC)
 * We do, but only if we actually spell the alphabet. Where, for example, would you look up Ärger, Ökonom, and über in a dictionary? Among A, O, and U, respectively, right? Note to non-German speakers: ä, ö, ü, and ß don't have places in the alphabet. Therefore, if you have to find an alphabetical order for words containing umlaute, you'd treat them as ae, oe, ue, and ss. Epsilon 10:24, 1 April 2006 (UTC)
 * Sometimes they are treated as just a, o, u and s, as well. So if you don't find a word in one place, look in the other.
 * "you'd treat them as ae, oe, ue, and ss" - Never heard of that, as far as I know, Ä is either listed after A (A, Aal, Antenne, Arbeit, Atom, azur, Ärger), or as if it was an A (…Arbeit, Ärger, Atom…). … Okay, I looked in my Duden (standard German dictionary), here how they do it: äöü is treated like aou and ß as ss, but before ss if the word is the same (i.e. Maße, Masse).

Recording speech
Hey there!

I just registered at the english Wikibooks (though I've been quite active in the german one before), and I'd like to contribute to this Wikibook. I am willing to record some of the dialogues in this lesson (or probably in some of the other lessons as well) and provide the audio files to this community for free and for free use. Since German is my native tongue, this shouldn't be much of a problem.

Please tell me what I am supposed to do.

Cheers!

Human Robot 22:25, 16 Apr 2006 (UTC + 0200)

Supplemental: Okay, since I didn't get any responses so far, I will simply go for it now, record the files, upload and link them. Human Robot 18:11, 21 Apr 2006 (UTC + 0200)

Hi @all

I've recorded some files and uploaded them. I hope, that the voice quality is ok, and that it's not too loud or too soft. If I should change anything with my settings, please tell me this. Thanks.

Sigrid

--Eskroni 15:00, 7 June 2006 (UTC)

Mistake in title
In title "Wie Heißt du?" the word "heißt" has to be written with a small capital, but this would change the name of the file/link. Maybe someone wants to change that.

--HolgiDE 10:35, 27 June 2006 (UTC)

Sentence Structure
'The common word order in a German sentence is the same as in English: Subject verb Objects. (SvO)'

 * That's not the case. The syntax requires the (finite) verb being the 2nd part of every main sentence; 'Fußball spielt der Junge' is equally correct, but now the object is stressed. (Translation: 'Soccer is the game the boy plays' or sth. like that) The German syntax requires the finite verb to be the first part of every question, apart from interrogative pronouns, and requires the finite verb to be last part of a subordinate clause.

 * The standard word order is subject-verb-object. However, you can place almost any part in the first place, in particular objects and adverbs. But this is not the standard word order. --Martin Kraus (talk) 08:41, 26 June 2010 (UTC)

Umlauts
This is a sentence from the section about umlauts: "In writing, the umlauts are sometimes substituted with the vowel plus e, i.e ae, oe and ue." That i.e. is confusing. The first time I read it I didn't get it... I understood what the sentence means, but I just didn't get the examples it was showing because of the i.e. Maybe it should be changed to "for example". 84.9.187.195 12:40, 22 August 2006 (UTC)

Formation
Is the formation of "Ich heiße Asd" something like "I'm called Asd" or "I'm named Asd"? Just to know, 'cause in portuguese it's really much like that "Eu me chamo Asd" (literally: "I call myself Asd") being used more than "Meu nome é Asd" (literally: "My name is Asd"). 200.230.213.152 23:34, 26 November 2006 (UTC)

It's just "Ich heiße Asd." There's no structure to it to compare it to in English or Portuguese. "Heißen" is a verb that just means "to be called ...", "to be named ...", "to have the name/meaning" etc. Ich = "I" heiße = "am called", "am named", "have the name".

Names
hi. in the names section on this page in the little blue box it says that "Wie heißt ihr?" means "what are your names?" but then it says (outside the blue box) that the plural form is "Wie heißen..." I'm very confused.
 * It depends on who or what you are asking about. Wie heißt ihr? is how you ask a group of people what their names are; Like "What are your(plural) names?" Wie heißen sie? would be how you ask ABOUT a group of people; Like, "What are their names?" hope that makes sense. Also NB: Wie heißen Sie? (with a capital S) is the formal version of "What is your name?"

error in venn diagram
"guten morgen" means "good morning" and is not a form of goodbye

 * Good morning is also a form of goodbye in both German and English. In English it isn't as common anymore; don't know about German. Anyway, not an error.

 * "guten morgen" should be "guten Morgen" and is no longer a form of goodbye in German. I removed the Venn diagram, because of the typos in it. Also, it doesn't make sense to teach students who want to learn German about Venn diagrams. --Martin Kraus (talk) 08:37, 26 June 2010 (UTC)

Keyboard Shortcuts for Umlauts and Eszett
I notice that you provide keyboard shortcuts for Windows and Mac computers to enter German characters, but what about users of Linux. For them, you can simply say that they can find the "Character Map" under Applications>Accesories>Character Map from the GNOME Desktop.

Agomulka (talk) 02:49, 1 December 2008 (UTC)

Tagchen!
I've never heart someone saying "Tagchen!". Maybe in a small dialect? Some people say "Tachchen", but nobode would write that. 92.225.139.188 (talk) 20:48, 7 June 2010 (UTC)

 * I agree. However, you might pronounce the "g" in "Tagchen" as a "ch" and still write it with a "g". This pronunciation of "g" is actually quite common, e.g. for "König"; I also heard people pronounce the "g" as a "ch" in "Kollege". --Martin Kraus (talk) 23:32, 7 June 2010 (UTC)

 * I have removed "Tagchen" because it is not in the recording. --Martin Kraus (talk) 23:27, 9 June 2010 (UTC)

Servus
I think it´s wrong, that it´s only used in Eastern Austria. I´m from Bavaria and have often heard it there. I don´t know what it´s like in other parts of Germany, but I reckon they use it too.
 * In Northern Germany 'servus' is not used. However, you can here it in Munich. It is therefore not restricted to Austria, but I would guess that its not used anywhere outside the "Austro-Bavaria hemisphere". 85.179.37.72 (discuss) 22:38, 6 February 2011 (UTC)

Ich heiße_...
Note, that in German, unlike in English, there must be a space in front of the ellipse (…), if the sentence and not the word is not finished. 92.225.139.188 (talk) 20:51, 7 June 2010 (UTC)

 * True, be bold and change it, please. --Martin Kraus (talk) 23:33, 7 June 2010 (UTC)

Splitting the Lesson into 3
Since there is far too much content in this beginner lesson, I suggest to split it into 3 lessons corresponding to the 3 dialogues. Any concerns about this? --Martin Kraus (talk) 23:31, 9 June 2010 (UTC)

 * I've reorganized the content to prepare for splitting the lesson into three lessons. The actual split will affect a lot of pages because the following lessons have to be renumbered; therefore, I will first reorganize the content of all lessons before I actually split the file into multiple files. --Martin Kraus (talk) 21:18, 23 June 2010 (UTC)

Video

 * http://www.youtube.com/watch?v=jNzAjc8Pf2g
 * The video is based on the dialogue in the lesson. The link was added at 02:08, 1 November 2010, by . (Please sign your contributions!)

Tschüs(s)
Tschüs should better be written with one 's' only, because in some regions the 'ü' is long, especially in the north. However, according to LEO also the spelling with two s is correct. 85.179.37.72 (discuss) 22:33, 6 February 2011 (UTC)

 * Where I live (in Kaiserslautern in Rhineland-Palatinate), people say Tschüss with a short ü, thus the spelling with two s is more appropriate here. In the old pre-1996 orthography, it would have been spelled Tschüß. Pelzflorian (discuss • contribs) 23:01, 19 March 2014 (UTC)

Ciao
I'm wondering, why the Italien 'ciao' is taught here as a common German word. You rarely here it and never write it in German, and until I read it here, I probably would have written it 'Tschau!'. It is very informal. 85.179.37.72 (discuss) 22:33, 6 February 2011 (UTC)

Pronunciation
I feel that a short guide to German pronunciation should be given at the very beginning of this course. I know giving a section on German pronunciation can be repelling (and scaring) to the new learner, but such a section will help him avoid a lot of effort in guessing the pronunciations. A little persistence from the student will make his life a lot easy.

Dialog 1 – Names
The names ‘Franz’ and ‘Greta’ are out of fashion for decades. It could be a dialogue between 80 year old people, but German teenagers are nowadays more likely called ‘Felix’ and ‘Sarah’. Have a look at to get an idea. -- Sloyment (discuss • contribs) 10:23, 31 July 2011 (UTC)

 * Feel free to change the names consistently and rerecord the dialogues. But please do not change the names before you have recorded and uploaded the new versions of the audio files. :) And, for the record, I know a German girl called Greta who is about 10 years old now. --Martin Kraus (discuss • contribs) 13:42, 31 July 2011 (UTC)

even if this is from 2011. if you'd looked closely at your reference, you'd noticed that greta is still in the top 60. admitted franz is out of fashion, but not that bad. I'm only 40 and we had 3 franz in class. 93.185.141.171 (discuss) 06:54, 4 September 2012 (UTC)

Dialog 1 – “Kennst du den Lehrer?”
This phrase is unidiomatic, i.e. it can be understood, but nobody would say it in that way. More realistic alternatives would be “Sag mal, weißt du, wie der Lehrer heißt?” or better “Wie heißt eigentlich unser [neuer] Lehrer?”. “Kennst du den Lehrer?” actually means “Do you know him personally?”, to which you could answer e.g. “Ja, wir sind gut befreundet.” or “Ich kenne ihn nur vom sehen.” -- Sloyment (discuss • contribs) 10:23, 31 July 2011 (UTC)

 * I think the question is OK in this context because it kind of asks whether you had him as a teacher before. More importantly, it is grammatically easier to understand than other alternatives. --Martin Kraus (discuss • contribs) 13:48, 31 July 2011 (UTC)

Trouble is: Kennst Du den Lehrer which is a literal translation of do you know our teacher, doesn't mean the same. The German phrase 'kennst Du' means if you know him (personally). Better would be 'Weißt Du wer unser Lehrer ist?" Do you know who our teacher is?.93.185.141.171 (discuss) 06:43, 4 September 2012 (UTC)

 * While one may prefer your form, 'Kennst du den Lehrer?' is not wrong. It is as acceptable as the English translation 'Do you know the teacher?'. And it's simpler than your proposal. Pelzflorian (discuss • contribs) 22:56, 19 March 2014 (UTC)

title: Talk:German/Level I/Wie heißt du


text: User:JWSchmidt/images

title: User:JWSchmidt/images


text:
User:WarrenWilkinson

كس امك

title: User:WarrenWilkinson


text:
File:Electronics Resistance Copper.PNG

A diagram of a copper conductor

title: File:Electronics Resistance Copper.PNG


text:
Cookbook:Polenta

| Vegan cuisine | Side dishes

Polenta is a dish of cooked cornmeal. It is delicious topped with your favorite tomato sauce or with an assortment of grilled vegetables. Chilled, firm polenta may be served cut into triangles alongside chili or other hearty stews. Leftover polenta may be cut into strips or triangles, coated in seasoned bread crumbs and grated Parmesan cheese, and fried in olive oil. Like pasta, the possibilities for this versatile dish are virtually endless, so feel free to experiment with additions and toppings.

Ingredients

 * 1 cup cornmeal
 * 4 cups water
 * Salt to taste

Standard method

 * 1) In a heavy saucepan, bring the water to a boil. Add the salt.
 * 2) Stirring constantly with a stainless steel whisk, pour the cornmeal into the water in a steady stream.
 * 3) Reduce heat to a slow simmer and keep stirring with the whisk until it starts to boil.
 * 4) Cover and continue to cook, stirring every 2–3 minutes with a wooden spoon, always in the same clockwise direction. The time necessary for the porridge to be correctly cooked and thus well-digestible is 45 minutes. If the porridge gets too thick, add some hot water or skimmed milk to obtain a more creamy porridge. Check frequently to see if more salt is needed.
 * 5) For eating polenta hot from the pan, put a tablespoon of water in a deep ceramic dish and scrape the polenta into it. Serve it with a big wooden spoon.

Quick method

 * 1) Boil the water on the stove, then pour it into a large microwave-safe bowl with the salt.
 * 2) Stirring constantly, pour the cornmeal into the water in a steady stream.
 * 3) Cook the polenta in a microwave oven on medium power for 2–5 minutes, or longer for a larger serving. Remove from the microwave and stir vigorously. It will not cook evenly, and this stirring helps prevent lumps.
 * 4) Repeat this process until the polenta is thick, then proceed as above.

Really quick method

 * 1) Boil the water, toss in the salt and cornmeal, and microwave on medium power for 5–8 minutes (depending on quantity).
 * 2) Remove from microwave and stir like crazy to smash all of the lumps.
 * 3) Repeat if you need to thicken it some more, stir, and blend with the few remaining lumps.

Notes, tips, and variations

 * Just before you take the polenta off the heat (i.e. when it's almost done), stir in any of the following:
 * 2 tablespoons olive oil or butter and ½ cup grated cheese
 * 2 tablespoons olive oil, 2–3 cloves of minced garlic, and ¼ cup chopped sun dried tomatoes (drained if in oil)
 * ½ cup canned sweet corn kernels and ¼ cup sliced green Spanish olives
 * 1 minced seeded jalapeño chili and ½ cup grated cheddar cheese
 * 2 tablespoons butter and ½ cup crumbled gorgonzola cheese, topped with caramelized onions
 * To eat the polenta roasted, scrape the polenta into a non-stick pan or ceramic dish (or some container that will release it when it cools), and cool completely until firm and loaf-like. Cut it into slices, heat it in the oven or grill it, and serve with whatever topping you desire.

title: Cookbook:Polenta


text:
User talk:80.131.79.1

Could somebody block this asshole? He's spamming.

title: User talk:80.131.79.1


text:
Talk:Electronics/RCL

What would be nice is some pictures of the various forms of dampening.

Damping, not "dampening". Dampening is sprinkling water upon.

title: Talk:Electronics/RCL


text:
Authoring Webpages/How to write for the web

Introduction
In the previous chapter, you have learned how to actually create a webpage.

To reiterate, you should have learned

 * that webpages consist of text with markup tags;
 * that the markup is part of a language called HyperText Mark-up Language (HTML);
 * that HTML must be valid, for various reasons;
 * that you can use a text editor to write HTML; and
 * how to apply some basic HTML elements to a text, such as paragraphs (p), links/anchors (a), important and less important headings (h1, h2), images (img), etc.

In other words, you have learned some of the mechanics of creating a webpage, and if you have followed the exercises, you actually gained some experience in writing webpages.

Now, you will begin to learn how to apply that knowledge in a meaningful way.

As we observed before, there is no right or wrong way to make a webpage. The page may consist of valid or invalid HTML, but whether a page is successful depends solely on the goals you have set yourself and whether they were met. However, we have also noted that there is no way of knowing whether the goals were met for all visitors.

Generally, your goal will be to tell the world a story.

If you manufacture lawnmowers, your goal with a webpage may be:

 * to entice people to buy your lawnmowers
 * to teach customers about how to use their lawnmower
 * to educate people about the dangers involved with lawnmowers
 * to show stock-holders in your company how business is going
 * to make it easy for the press to write about your lawnmowers
 * to impart your love for making lawnmowers onto others
 * to offer a community of lawnmower minded people the chance to interact with each other
 * to show suppliers how to reach your factory
 * to warn customers of shoddy look-a-like products
 * to accuse competitors
 * to respond to accusations of competitors

This list is endless. Who knows why somebody makes a webpage? There could be a million reasons.

But once you have committed yourself to telling your story, it would help if you could get your story across.

General writing skills are beyond the scope of this textbook. There are other Wikibooks (under development at the time of writing) that teach you exactly this. See for instance How to write an essay.

Reading problems on the web
Although few hard facts are known about this, it is generally assumed that reading from a screen is harder than from paper. For instance, it takes about 30% more time to read a text off a screen than off paper. Although little is known about the reason for this, it could be because most screens are static, while readers who use paper generally can move the paper around. Another theory holds that because the resolution of text on paper is much higher than that on screen (300dpi vs. 100dpi), it is 'easier for the eye' to read text off paper.

Most visitors browse websites using a browser that displays the contents of a webpage on a screen. The standard typography of web browsers seems to accommodate for a harder reading experience: paragraphs are separated by empty lines.

Regardless of how difficult it appears to be to read off a screen, web surfers have shown a marked preference for lay-outs that make it easier to scan a text for important points. Some of the qualities of these lay-outs are:

 * list-type information in lists
 * clearly marked hyperlinks
 * no horizontal (sideways) scrolling
 * all the important information above the 'fold'
 * inverted pyramid structuring of text

Often, visitors will print out text that they want to read with attention, while they skim over text that does not warrant such close scrutiny.

Information scent
Whatever they are searching for, most web surfers follow a similar strategy in hopping from page to page. They will 'scan' (skim through) a webpage, looking for interesting information. They will seek out elements that seem most promising to deliver that information, such as headings, emphasized text, and hyperlinks. If within the first few seconds a webpage does not seem to promise interesting information, the visitor will hop on the most promising hyperlink out of there. If there are no promising hyperlinks, visitors may even use the Back function of their browsers to return to a previous page.

The trail of promising elements is similar to the trail a bloodhound follows when hunting prey. It is therefore said that elements on a webpage emit an 'information scent'. The stronger that scent, the more likely the user is to follow it.

However, if a certain type of element has been producing false trails often, users will start turning away from such elements. For instance, although animated content is much more attention grabbing than static content, visitors turn away from animations more and more. This may be because web surfers have started to equate animations with advertisements; and advertisements rarely contain the sort of information the visitor was looking for.

By knowing how to make a webpage more accessible to those who use graphical browsers, and by knowing how to apply the right amount of 'scent' to certain elements on a page, the webpage author arms himself with the right tools to reach his audience optimally.

In the following, we will take a look at a couple of such tools.

Links vs. Text
The term Hypertext consists of two parts: 'hyper' and 'text'. Hyper is originally a Greek word meaning 'over', 'beyond'. Hypertext is something that takes text to a new level; but it still remains text. Hypertext has all the properties text has, and then some.

Although the title of this section makes it seem so, the extra properties of text, i.e. the (hyper)links, are not at war with the original text. At least not all the time.

When the theories of the web experts are correct, a web user surfs from page to page, following a trail of information scent. Whether that user is looking for a specific piece of information and trying all likely avenues that may lead to that piece; whether a user is looking for specific information, but gets side-tracked by other information; or whether a user is not looking for information at all, but just for some fun; all seem to be using the same strategy of following a trail of promising leads.

The longer a visitor stays on a page that does not hold his interest, the more the likelihood increases that the visitor starts looking for a way to escape. Although the promised information or fun may lie in the plain text that is presented on a webpage, all the escape routes are embedded in hyperlinks. Chances are, therefore, that any text that does not immediately captivate a visitor's attention, is unlikely to be read later on, unless much of the preceding text has already made abundantly clear to the visitor that this is where he wants to stay.

Let me repeat again that it is not the author's task to entertain the reader. But an author who does not want to entertain readers, will find himself without an audience. Similarly, an author who sets out to maximize the sense of reward someone gets from reading his work, will reach the maximum audience for that type of work.

???more to follow

The fold
The fold is a term that could in some sense be used for all media, but is pretty useless when speaking of streamed media such as speech. It is a term used for visual browsers, meaning the bottom edge of the first displayed part of a webpage.

For instance, if a webpage consists of fifty lines of text, but only the first twenty are displayed, the fold is beneath the twentieth and above the twenty-first line.

That may seem to be an arbitrary position to give its own name, but it is not, because webpage visitors will generally look at what's above the fold, not at what's beyond.

Unfortunately, it is not a very useful metric, as each visitor has his web browser set up in different ways, and so for each visitor the position of the fold may differ.

However, it teaches us that things that need to be viewed by as many visitors as possible, need to be as high up on a page as possible.

The inverted pyramid
So far we have discussed the difficulty with which a visitor reads a webpage off a screen, and with which haste he does so. Forget to grab the right person's attention, and he will disappear to the greener grass on other webpages. The web is quite vicious like that: all your competitors are your direct neighbour.

In the section about the fold we discussed how it is important to maximize your readership by putting important information at the top.

The method of writing a text with the most important sentence first, the second most important sentence second, the third most important sentence third, etcetera, is called the Inverted Pyramid.

Traditional essay writing holds that a piece is structured as follows: introduction, expansion, conclusion. For most of us, it is pretty common practice to sit on important facts for awhile, and only reveal them as the piece progresses. As readers, we have become accustomed to text being structured like this, and are willing to show a certain amount of forgiveness when an author does not come to the point right away. On the web, we click away without even blinking our eyes when we encounter a text that does not immediately tell us what we want to know.

Pitfalls
So far, we have been stressing what happens when a visitor does not find the information he is looking for. But what happens when the visitor does find what he is looking for: does web text still need to be as oddly contorted as described before in order to appeal to the visitor?

One would hope not. How would Alice in Wonderland read if we had put the most important facts first? If we had put links to more interesting literature in the text? If we had forgone all artistic ambition just to satisfy some weary surfer, who wasn't going to read our text anyway?

The usability extremists would say, yes, there are no artistic values--just a new world, with new rules.

Unfortunately for them, people do read on the web. They are moved by what they encounter. They have ways to circumvent the difficulties of the web medium. For instance, people who find an interesting text on the web often print it out, so that they can read it from an easier medium.

I would also argue, without any facts to back me up, that the nature of a text plays a role. Informative and persuasive texts may be constructed according to the guidelines given before, whereas entertaining texts may be constructed in the old-fashioned, pre-web way.

If you are trying to sell me something, for instance, there's really no need to fluff up your text with "marketese". More likely than not, I will hit the Back button of my browser faster than you can say 'percentage'.

If you are trying to inform me of something, I might be more lenient. The trade we are making (you get my attention, I get your insights) is much more immediate, and therefore worth more to me.

But even the authors of entertaining webpages can learn something here. The most important thing: you write for an audience. The medium plays a role in that. A hard rock band must use loud speakers. It's what the audience expects. (And of course, the hard rock band that knows this can play on this, and show their soft side in an 'unplugged' session--but such things are better only tried by those who understand their medium.)

Even if the entertaining text is going to be printed out, even if the user is going to sit in front of his screen and persevere through your entire, brilliant play, some of the methods outlined before make sense.

Should you not use the inverted pyramid, you should at least use headings for headings, don't fiddle with font sizes (yes, this is unfortunately possible), let paragraphs stay separated by blank lines, etcetera. It is not rare to find that some author of science fiction stories has found out a way to display their story the same as on paper--forgetting in the mean time that he is not publishing on paper, and losing part of his audience.

Most of the promotional value of an entertaining text is in the text itself. Entertainment is highly valued: if what you wrote is good, others will link to it, including search engines.

Usability and Accessibility
The World Wide Web Consortium has produced a set of Web Content Accessibility Guidelines that provide guidance on some areas of writing web pages. The guidelines are quite daunting at first. Don't try to understand them all in a single reading. Some guidelines are easy to follow whilst others can require significant effort.

Watchfire's WebXACT is a popular free online tool for checking pages for accessibility. Although it can only check some of the guidelines and occasionally fails pages that do meet the guidelines it is a good starting point for learning the guidelines.

Checkpoint 10.4, "Until user agents handle empty controls correctly, include default, place-holding characters in edit boxes and text areas.", is now considered unnecessary and has been removed from the draft of the next version of the guidelines. See the UK's Royal National Institute for the Blind's article Place-holding text in form elements for more information.

Checkpoint 4.2, "Specify the expansion of each abbreviation or acronym in a document where it first occurs." It is now considered good practice to markup all occurrences of an abbreviation instead of just the first occurrence. HTML 4.01 and XHTML1.0/1.1 have two elements for marking-up abbreviations. The  element is used to markup any abbreviation. The  element can be used to markup acronyms. Since acronyms are a special type of abbreviation they can also be marked-up with. Abbreviations that are not acronyms should not be marked-up with.

Exercise 3-1
Behold the following text: "It is always the dead that are praised, or so claim those who are unsuccessful while alive. Perhaps this is so, partly because some people only revere that which has passed. However, works that have withstood the test of time, have withstood its scrutiny. Long-dead authors that are still remembered, are remembered because of the quality of their work. And no work can be stiled that of a genius, until other works have come along against which it can be compared." (Free after Samuel Johnson's "Preface to Shakespeare".)

Rewrite this paragraph using the inverted pyramid.

Answers
For answers, see Answers to Questions and Exercises.

Previous: Creating a simple page - Up: Table of Contents - Next: Adapting a webpage for visual browsers


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Electronics/Humor

Sample joke: (rough draft)

Q: How do you tell the difference between elementary particles? A: Protons are positivists, electrons are negativists, and neutrons have no opinion.

Two atoms are walking down the street. The first atom says to the second atom "I think I lost an electron!" The second says "Are you sure?" To which the first states "I'm positive!"

title: Electronics/Humor


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User talk:67.112.108.87

A scale? What do you mean?

which page?

title: User talk:67.112.108.87


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Cookbook:Potato-Chickpea Curry

| Curry | Vegan cuisine

Ingredients

 * 1 small onion
 * 2 cloves of garlic
 * Olive oil
 * 1 tbsp curry powder
 * 1 can coconut milk
 * 3 potatoes, chopped (Yukon gold are good, but use whatever you like)
 * 1 can chickpeas (unsalted, if available)

Procedure

 * 1) Chop the onion and mince the garlic. Sauté them in olive oil in a saucepan for approximately 5 minutes.
 * 2) Add the curry powder and fry for a couple minutes more.
 * 3) Add the coconut milk and the potatoes. Simmer, covered, for about 20 minutes.
 * 4) Drain the chickpeas, add them to the pot, and simmer for about 20 minutes more, or until the potatoes are cooked.
 * 5) Serve with basmati rice or whatever you prefer.

Notes, tips, and variations

 * If the curry powder you use isn't spicy enough for your taste, try adding a half-teaspoon of cayenne pepper.
 * If doubling the recipe, do not double the chickpeas.

title: Cookbook:Potato-Chickpea Curry


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Cookbook:Tofu Pancake

| Vegan Cuisine

Ingredients

 * Flour
 * Cornstarch
 * Soy milk
 * Salt

 * Tofu
 * Spices (e.g. shoarma, gyros, powder from the general store, you name it)
 * Onion, chopped
 * Garlic, minced
 * Fresh herbs (e.g. coriander, etc.)
 * Raw vegetables (e.g. lettuce, etc.)
 * Chili sauce

Procedure

 * 1) Combine flour, cornstarch, salt, and soymilk to make a batter.
 * 2) Fry the batter in a greased skillet over medium heat to make pancakes. Reserve pancakes.
 * 3) Mash the tofu with a fork, and mix in the spices.
 * 4) Fry the onion and garlic in a skillet with a dash of oil. Add the tofu, and fry until it has a granular texture.
 * 5) Put a pancake on a dish, and top with the cooked tofu and some of the vegetables/herbs. Drizzle some chili sauce over the top, and serve.

title: Cookbook:Tofu Pancake


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User talk:213.84.111.66

All info i added was in the public domain. It was taken from http://www.infoanarchy.org/wiki/wiki.pl?Veganism/Recipes

title: User talk:213.84.111.66


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User:Wanderer~enwikibooks

A student of everything, I seek to seek to understand the limitations of reality. I like brute force and am adverse to math related rigor. My strengths include perturbation of reality and plot devices, heuristics, video game design, programming, Computers, Physics, Math, Chemistry, Engineering, Bio, Cooking, and 3D packing.

To date I have started the Electronics Wikibook on Mar 8, 2004, which I hope to finish someday.

As background for the Electronics Wikibook, I started the Physics in English Wikibook on May 5, 2004.

I also started the Book For Geeks Wikibook on Apr 14, 2004, which I hope to work on some day.

Besides these books I have a number of other books I could write.

Personal bookcase (Things everyone should know):

 * Technical books:
 * 1) Physics in English: Writings on a number of high level topics.
 * 2) Electronics: Build your own computers and radios.
 * 3) Languages_bookshelf: Pick a language any language.

 * Information Theory books:

 * Practical books:
 * 1) Book For Geeks: How to deal with the real world.
 * 2) Cookbook: An easy way to improve your life and save you money.

title: User:Wanderer~enwikibooks


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Organic Chemistry/Introduction to reactions/Halohydrins

Halohydrins are formed in addition reactions with alkenes, and either an aqueous solution of a halogen or the corresponding hypohalous acid (eg HOBr or HOCl).

Halohydrin formation uses a cyclic bridged ion as an intermediate. Because of this, the stereochemistry of the reaction process is anti.