Theory is a contemplative and rational type of abstract or generalizing thinking, or the results of such thinking. Depending on the context

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406 views

Why don't infinitely many sinusoidals exist in an oscillator circuit?

A sinusoidal oscillator, takes the ambient thermal noise or any imbalance in the circuit as input and gives out an oscillation. This kind of oscillators are called to be linear. By the nature of a ...
2
votes
2answers
97 views

When is it theoretically possible to fit PCB circuit on x Layers (emphasis: x =1)

When is it theoretically possible to fit a given circuit on a certain number of layers? (Presumably PCB layers.) What is/are the name of the mathematics/algorithms that might determine this, or ...
5
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3answers
414 views

Theory question about “j” imaginary unit (AC circuit analysis)

I have just started to learn about AC network analysis and have some questions about "j" (or "i" on my calculator), the imaginary unit. My book doesn't go into a great deal about this, and jumps ...
6
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2answers
683 views

Why do op-amps keep amplifying?

I was reading an old copy of Horowitz and Hill's The Art of Electronics and I am trying to wrap my head around operational amplifiers in negative feedback circuits. As the book explains, as the ...
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1answer
139 views

Would it be practical to build a chip that can do this math?

I was theorizing a new kind of 64-bit number for use in data storage, but then started wondering if it could become practical if created in hardware. (I believe it would be too slow if only software ...
0
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3answers
104 views

Why doesn't linear resistance scale proportionally with the square of length?

I have an in depth question about basic proportionality of resistance. Why doesn't it scale with the square of length? I ask this because what is causing the potential difference on two leads is ...
0
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1answer
44 views

Absolute and relative permitivitty

Principles of Electronic Materials and Devices - Hasap, pg: 585, he says: $$\epsilon_r = \frac{Q}{Q_0} = \frac{C}{C_0} = \text{relative permittivitty}$$ Then he says: It is important to remember ...
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vote
1answer
60 views

Induced dipole moment and 'electronic polarization'

Principles of Electronic Materials and Devices - Hasap, pg: 586, he says: The induced dipole moment depends on the electric field causing it. We define a quantity called the polarizability a to ...
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3answers
144 views

Is there a maximum possible voltage?

This question got me to wondering if there is a maximum theoretical voltage. It seems to me there's a limit to how much positive or negative charge you could have--say, a container full of electrons ...
3
votes
4answers
504 views

Design vs reality and what to do when they differ

I've been trying to focus a bit more on Analog circuits lately and found that my design and actual results often don't match up exactly. An example is a Pierce oscillator I built a while back, the ...
2
votes
3answers
314 views

How can the SI unit of resistivity [Ωm] be interpreted?

The way I interpret the resistance \$R\$ of a resistor, which has dimensions \$ [\frac{\mathrm{V}}{\mathrm{A}}] \$ is: how many volts must be applied across the resistor to achieve 1 ampere of ...
2
votes
3answers
115 views

Voltage and Current along a Wire

In this question I am referring to this article. At first I was looking for a physical explanation of the fact that energy or the signal, respectively, travels much faster through a wire than the ...
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1answer
72 views

Am I doing this right? (LED's to music)

simulate this circuit – Schematic created using CircuitLab I have been charged with designing and making a circuit that makes LEDs brighten or dim to an audio source. At the time I ...
3
votes
1answer
70 views

Resistivity and resistance. Permittivity and?

We know that resistance is dependent on both the materials resistivity and the geometry of the material. For a cylindrical or rectangular material the resistance is: $$R=\rho*\frac{l}{A}$$ where l ...
0
votes
2answers
97 views

At what resistance do I not see a voltage drop across a resistor?

If I have a circuit like this and measure the voltage drop across the resistor I get a value, regardless of what resistor I use: However, if I stick a piece of wood in there instead of the resistor ...
0
votes
3answers
69 views

Is it possible to have a continuous quantized signal or a discrete infinite precision signal?

When converting an analog signal to the digital domain I understand that one does two things. An analog signal is continuous and must be sampled in to discrete time segments (Discretization) The ...
9
votes
4answers
799 views

Where does U for voltage come from?

I believe in Europe the letter U is commonly used for voltage in (eg.) Ohm's law \$U = I × R \$. I think I understand where the letter V came from, commonly used in North America. But what's the story ...
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3answers
102 views

Biological 'Black Box' - how to test for underlying logic?

Firstly, I am a neuroscientist - so bear with me! I have a collection of connected brain cells (network) and a means of recording the electrical output, as well as manipulating the input to the ...
5
votes
1answer
220 views

What are the technical challenges to store electricity from lightning strikes? [duplicate]

I ask myself that question every time I watch a Tesla documentary. So, let's get some answers down so the smart ones can think about it and we can clean-up our environment. There is free electricity ...
10
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7answers
2k views

When people talk about a device “drawing” current, what do they mean? Why do devices under load “draw” more current?

In my (extremely rudimentary) understanding, the amount of current flowing in a circuit is determined by a) its resistance, and b) the voltage of the power source (voltage from beginning to end), ...
1
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1answer
77 views

Radios and Power [closed]

RF newbie here. Lately I've been experimenting with RF. I built some simple oscillators, managing to get a tank circuit working as well as buffering the 1 megahertz output of a tin can oscillator. ...
2
votes
4answers
130 views

Series/Parallel DC circuit analysis training issue

I'm blocked in this exercise. I don't get how I can compute R1/R2/R3 voltage. Here's the schema : simulate this circuit – Schematic created using CircuitLab So I was able to calculate ...
2
votes
2answers
107 views

Current divider rule calculation issue

I'm doing the exercises from Wisc-Online. This one I think they are really great to learn and practice and have already done a bunch of their practical trainings. But here I'm starting to be crazy. I ...
0
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2answers
915 views

What does common mode voltage stand for in an instrumentation amplifier?

I was reading a text about instrumentation amplifiers. I couldn't find any easy explanation what really common mode voltage means and its importance.
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3answers
357 views

How does a domestic appliance “know” how much current to draw?

I have a small wall plug which takes 240V 50Hz AC from the mains, and can give me 500mA 5V DC. I suspect there is a transformer stepping the voltage down and a bridge rectifier converting the AC to ...
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1answer
64 views

How would i go about finding Rl when rl is r3

How would i go about finding Rl :/ I'm so lost iv looked for examples and all they have done is confuse me
6
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4answers
196 views

Another question concerning transistors

I know it's been asked 1,000,000 times how/what/why transistors work and I feel like I've read every answer but I still struggle with the basics. The struggle for me is the difference between ...
2
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4answers
244 views

Resistors and the water analogy

The the most prevalent analogy for understanding electricity is the water hose one. I personally like this because it's very understandable but I have a question about how this works with resistors. ...
15
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6answers
1k views

Do electrical devices “take what they need”

One concept of electronics I have a hard time understanding is if things like motors, actuators, solenoids etc. use as much power as they need or what you give them. If a motor needs 12 volts and ...
0
votes
0answers
154 views

unity opamp - what it did for my digital volume control circuit

simulate this circuit – Schematic created using CircuitLab So I took apart the control pod for my 5.1 surround sound logitech speakers. Inside I found a 50k pot for the volume. At first I ...
4
votes
2answers
143 views

Differential equation into circuit and back - good book

I have had some electronics, but we only built our circuits and then measured the input / output signals with oscilloscopes... Today I found an interesting question on physics stackexchange where ...
8
votes
3answers
506 views

How does control theory apply to my real-world processor-controlled boost converter?

I have a limited understanding of control theory. I dealt with poles and zeroes and transfer functions in school. I've implemented several microprocessor-based control schemes for DC/DC converters. ...
7
votes
2answers
381 views

What if you put a capacitor betwen the plates of another capacitor?

Based on: Is there a dual of the transformer? The picture of the capacitor inside another capacitor seems viable to me. If a transformer is two inductors with a common magnetic field, its dual ...
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2answers
146 views

How and why is “floating input” a valid state for RF/IR encoder IC's?

RF/IF encoder/decoder IC's such as this one, will accept the address-pin in one of 3 states: Floating High Low As per this excellent answer, I believe "Floating" input can assume either High or ...
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1answer
163 views

Calculate current in branch using Thévenin's theorem

E1 = 20 V E2 = 5 V R1 = 10 Ω R2 = 20 Ω R3 = 10 Ω R4 = 10 Ω R5 = 5 Ω Calculate Ix. It's obvious that the Thévenin's theorem should have been used, but the implementation is a bit ...
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votes
1answer
181 views

How correct is electric theory taught in school? [closed]

http://skeptics.stackexchange.com/questions/15779/is-the-electric-theory-commonly-taught-completely-off I made a question on skeptics about homepage, that made some pretty big claims about electric ...
5
votes
5answers
756 views

Are E and B fields in phase in electromagnetic radiation?

I recently wrote this answer, in which I said: Radio waves are electromagnetic radiation. Electromagnetic radiation contains of two components, one electrical and one magnetic. These components ...
0
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2answers
122 views

What idea/field in electronics is revolutionary nowadays [closed]

i realize that back then in the 30's-40's Von Neumann architecture was revolutionary, parallel at MIT, information and communication theory, and vacuum tubes were revolutionary fields, in the 70's ...
1
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2answers
224 views

Basic circuit analysis - diferential equation

This is the circuit I got from an example in a book "Practical Electronics for Inventors", on page 48: How can one understand that \$0=R\frac{dI}{dt}+\frac{1}{C}I\$ implies ...
4
votes
0answers
73 views

What course of study is important for someone wanting to make analog audio equipment? [closed]

I do not have a background in electrical engineering. I do have experience building audio equipment from kits and I can build circuits from schematics diagrams. What I would like to do is to be able ...
1
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3answers
408 views

How to light a fluorescent lamp?

There are a lot of circuits on the internet for lighting fluorescent lamps. But they don't reveal the working mechanism of the lamp itself. I'm more concerned about the theory rather than the ...
3
votes
4answers
482 views

Early Effect, Ebers-Moll, Common Emitter Resistance, reverse alpha/beta and saturation current

Ive been reading Sedra/Smith's Micro Electronic Circuits book, and it has a lot of info which I like, however I dont know how much of it is actually practial and useful, for instance it talks about ...
0
votes
2answers
366 views

What sort of applications does the normal distribution have in electrical engineering? [closed]

Need to know just two. Sorry for posting this here (arduino). Seems there isn't a soft-questions tag. Thank you for your help.
4
votes
3answers
3k views

How to calculate a current being drawn by a full wave rectifier diode bridge?

I've been studying power supplies and diodes, all books I've read discuss a great deal of things, but there's something I haven't found, and that is how to calculate how much current a bridge ...
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votes
1answer
245 views

Z-parameters. Is Z12*Z21 always greater or equal zero if a circuit has only resistors? [duplicate]

Possible Duplicate: Is equivalent resistance always lower if we add a resistor to a passive electronic circuit? Since my last question was probably badly formed and misunderstood this is a ...
0
votes
2answers
161 views

LC circuit poor man theory

Ok, let's suppose we want to explain the resonant frequency of an LC circuit. By kirchoff laws is not so difficult ending to the equation: By using the Wolfram alpha engine I end up with the ...
0
votes
2answers
730 views

Which books should I read to gather practical and useful electronic design skills?

I need some guideance from the experienced users here, I need to know where to focus my studies: Ive been reading several electronic books, and they are quite different, I decided I want to re-learn ...
5
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2answers
202 views

Voltage divider ambiguity

considering the following circuit : ...
2
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2answers
1k views

AC Voltage source terminal polarity and grounding

Ill try to make it as clear as possible. This may seem like a simple question, but it is something that I havent quite figured out. It has to do with polarity on the leads of an AC source. Every book ...
2
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2answers
910 views

Discharging a capacitor through a resistor and an LED in series

Suppose you have a capacitor of capacity \$C\$ and initial voltage \$U_0\$, a resistor \$R\$ and a LED with threshold voltage \$U_S\$ (\$U_0 > U_S\$) in series. Now I want to calculate duration ...