Electronics is the study of electric circuits and electrical components, and the design of useful devices. Some questions in this tag may be more appropriate for the [Electrical Engineering(http://electronics.stackexchange.com/) SE site.

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172 views

Concepts in Gabriel Kron's later papers

Gabriel Kron was an important research electrical engineer known for applying differential geometry and algebraic topology to the study of electrical system. Towards the end of his career he published ...
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1answer
66 views

What will be the effect of placing a light source very close to a photodiode?

What will be the effect of placing a photodiode really close to a laser source and what should be the appropriate distance between a light source and photodiode to get maximum output current?
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3answers
688 views

How does Ohm's law apply to superconductors?

As radio amateurs we've all learned the various relationships of power, voltage, current and resistance as expressed in Ohm's Law. My question relates to the following simple circuit showing an ideal ...
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3answers
51 views

Can we have electronics with charge carriers OTHER than electrons?

Ions perhaps? Or other elementary particles with charge?
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1answer
88 views

How big was the first transistor?

The first working point-contact transistor made in 1947 by Bell Labs. I'm looking for specific dimensions, all I've been able to find is "Fits in the palm of your hand".
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1answer
219 views

Why is spectral sensivity of a photodiode expressed in A/W

Can someone explain me the meaning of the A/W unit of the photosensivity when reading a spectral response function of the wavelength characteristic of a photodiode?
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1answer
66 views

Why is electricity so successful (how to explain the variety of transducers we have discovered)

From piezoelectric crystals, to loudspeakers, microphones, hydrophones, strain gauges; electricity possesses the amazing ability to transfer energy/information to and from so many different media. I ...
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3answers
406 views

Is it possible to produce gamma radiaton using radio emitter?

As in the title, I'm wondering is it possible. I think it is possible, because we have powerful enough radiotechniques and gamma radiation are just EM waves, not particles. However I think is ...
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2answers
230 views

Electrical analogy for stress and strain

It feels like the relation between stress and strain (and other mechanical properties) is analogous to that of some electrical properties (voltage and current?). I'm comfortable with electrical ...
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1answer
19k views

What is the role of center-tapping in a full wave rectifier?

Note: I have already tried googling. Although similar questions have been asked on different forums, I couldn't find a detailed explanation, which I could really understand. Circuit diagram ...
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2answers
424 views

Explanation of NMOS processes

Gate (poly-Si + $SiO_2$) and $p^{-}$ silicon operate as capacitors. But how are voltages and charges applied? In order for inversion to occur, there should be charges formed in poly-Si, right? How ...
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2answers
28 views

Stroboscope's unit

Can someone please tell me why does stroboscope's unit is rps or rpm. Revolution per minute/second. Although the stroboscope used was an electronic stroboscope. Is it has something to do with the ...
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1answer
63 views

why some elements of same group cannot be used for doping semiconductors?

15th group elements like As, Sb, P can be used for doping whereas N and Bi cannot be used for doping even though they too belong belong to 15th group. Why ?
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1answer
82 views

Diodes (Forward biased)

Why does the width of the depletion region decrease,when the diode is forward biased?Is it because the ions have moved to p-junction,or n-junction? Please clarify.
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4answers
2k views

When does Thevenin's theorem not apply (modelling a power source with a ohmic internal resistance)

Most physics text books say that a power source can be modelled as an EMF with a internal resistance. This is also know as Thevenin's theorem or Norton's theorem. However I have read in some sources ...
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5answers
6k views

Current through the reverse biased junction in transistor [closed]

A transistor is a three terminal device. One terminal is called emitter, one collector and in between them is base. Now, during biasing the junction between emitter and base is made forward biased and ...
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3answers
49 views

EMF in circuits help?

Can someone explain EMF in the most simple way possible? I understand the equation i.e. $ε=I(R+r)$ but don't fully understand what is going on in the circuit.
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1answer
126 views

electron-gas theory of a metal (drude model) - intuition

I'm back to studying "Microelectronics" by Millman & Grabel (2nd ed.). The book makes some references to the electron-gas theory, and I found out to have some problems with my intuition. At each ...
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1answer
312 views

Question on Shockley's equation for FETs

I'm currently studying FETs (Field Effect Transistors) in Navy school. What I know so far is that in FETs, $V_{gs}$ is reversed biased, creating a depletion zone. What this means in plain English is ...
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1answer
20 views

Generator phase noise influence on its averaged signal

I need to estimate averaged signal of a generator with known phase noise and the amplitude noise can be neglected. The averaged signal of the generator is expressed as: $$ \langle A\exp{i(\Omega t + ...
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1answer
292 views

Calculate TEC efficiency

I am currently doing a small experiment using a Peltier to cool 250ml of water. My aim is to achieve the cooling of 250ml from 23degC to 8degC in under 20minuets which I have done by strapping the ...
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1answer
115 views

Spin FET Transistor

Spin FET Transistor. When a gate voltage is applied to a current of spin polarized electrons, a spin precession will occur. If this spin precession is enough to make the bulk electron spin ...
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1answer
132 views

What is the speed of electrons in a transistor?

What is the average speed of an electron in a MOSFET transistor, and how can you calculate this? I've heard people throw terms such as "drift velocity" and "Fermi velocity" around, but I've never ...
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2answers
208 views

Can you replace the backlight of a thin film transistor (TFT) with a mirror?

I basically know how TFT' displays work. They have on both sides a polarizing foil, in 90 degrees with the crystals in the middle modifying which light particles should pass through or not. The light ...
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1answer
885 views

How to understand exciton?

I know that exciton is an electron and hole orbiting around each other(at least that is what I have heard). So if the hole is a hypothetical particle with a plus sign, mining that it is a lack of an ...
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1answer
580 views

Electrical conductivity of an intrinsic semiconductor

On which factor does the electrical conductivity of an intrinsic semiconductor depend? It doesn't have an excess of charge carriers in fact, does it?
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3answers
293 views

Electronic filter

Can you explain, please, step-by-step how an electronic filter does work? For example, high pass filter. I know It's a trivial things, but I can't get it completely. Don't bring me formula and etc. ...
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2answers
873 views

In the diode equation, why the exponential $\exp$ and the ideality factor $n$ are there? What do they represent & what is their significance?

In the Shockley diode equation, why the exponential $\exp$ and the ideality factor $n$ are there? What do they represent & what is their significance? I have to work on Solar Photovoltaics, and ...
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2answers
340 views

Nodal Analysis of an electrical circuit

I have several doubts about solving circuits. Can any circuit be solved using Nodal Analysis? If some circuit can be solved using Nodal Analysis, can it be solved using Mesh Analysis too? Why do we ...
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1answer
212 views

Could a variable capacitor divider replace a Variac?

Hmmm... You can definitely drop down the voltage, and ideal capacitors don't dissipate any power. So it seems, at first glance, that you could use a capacitor divider as a lossless voltage step-down ...
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1answer
27 views

Why, microscopically, is the voltage drop across a resistor affected by the current through it?

If voltage is a potential difference, describing how much energy will be lost per unit charge as charge carriers pass through the resistor, why would the rate at which charge flows (i.e. current, ...
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0answers
49 views

Electrical conductivity of pool water [closed]

What is the electrical conductivity of pool water? I tried to find some information, unfortunately with no success. I need to know it to make an underwater electronic project. Thanks
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0answers
37 views

What technologies are available to measure distance? [closed]

I'm a programmer, I really lack of physics knowledge, I'm trying to make some basic design for a distance measuring simple system, for a social project I'd take as hobby. Basically I would have many ...
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0answers
70 views

Numerical Solution of 1D Boltzmann Transport Equation

I need to solve the one-dimensional Boltzmann transport equation in a semiconductor numerically, and I want to take a deterministic approach toward the problem (i.e. not use Monte-Carlo or similar ...
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1answer
93 views

Why do electron and hole mobilities decrease with temperature?

From page 35 of "Microelectronics" by Millman Grabel Mobility $\mu$ decreases with temperature because more carriers are present and these carriers are more energetic at higher temperatures. ...
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0answers
103 views

How is the bandgap reference diode so accurate? (temperature changes bandgap?)

I am studying about bandgap references (wiki). As a black box approach, (from what I know) it can be seen as a system which gives a stable voltage reference irrespective of the highly varying ...
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0answers
63 views

Graded semiconductors - hole concentration function of x

I'm stuck at page 37 of the (second ed.) of "Microelectronics" by Millman & Grabel, section "1-7 Graded Semiconductors". Before that section, it spent some time explaining the phenomenon of ...
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0answers
34 views

Discrepancy in introducing Schottky barrier

I have a problem regarding introduction of Schottky barrier in metal-semiconductor junction. Because of this barrier the energies of conduction band vary discontinuously and hence the potential is ...
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1answer
151 views

How do I calculate motor efficiency from voltage, current and RPM?

I have a setup where a motor is spinning at a constant (known) RPM, under no load. I know the power going into the motor (voltage * current), and I can find out the rotational kinetic energy of the ...
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2answers
134 views

How does electrostatic force affect electronic devices?

How does electrostatic force generated by two seperate plates having opposite charges affect electronic devices? I know that magnetic fields have some harmful effects to electronic devices but I am ...
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0answers
114 views

How do universal battery chargers work [closed]

How does a universal battery charger, such as this one work, i.e. how does it know what voltage, current and polarity is appropriate for the battery inserted? Do batteries have some form of protocol ...
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0answers
38 views

A voltage-controlled oscillator? [closed]

I already apologize for my medium english... I'm a french guy, not really gifted to recognize electronic circuits : In fact, I need to identify a circuit from is function. So, here is the block ...
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0answers
94 views

What does “although electrons enter and leave the diode, charge is carried by holes in the p-type region” mean? [closed]

I read this in an electronics book but I couldn't understand it: The flow of current through a forward-biased diode may be summarized like this. Electrons pass from the external circuit and ...
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0answers
59 views

The things to consider when choosing a mesh for an electron detector (MCP detector)

I am designing a electron velocity map imaging setup. I need a copper mesh just infront of the detector to accelerate the electrons towards the MCP detector. I am doing the instrument design for the ...
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1answer
100 views

Instrumentation handbook [closed]

Does anyone have any suggestion on a handbook of instrumentation? In particular NIM instrumentation... I would like an approach which will explain the techniques and how to use NIM modules. In ...
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0answers
141 views

Is there an equation for the magnetic field of a conductor attached to a magnet?

Let's say I have a hollow conductive rod, 10mm diameter (O.D.), and I place a magnet of known strength 50mm up the shaft. What is the microTesla (mT) or Gauss (G) of the magnetic field (or flux ...
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0answers
338 views

Algorithmic approach for applying Kirchhoff's Rules to circuit analysis

Working with Kirchhoff's rules, I am attempting to device an algorithmic approach to finding the unknowns of the problems, I am of a Computer Science background and I am finding it difficult to ...
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0answers
128 views

Simplifying a biquadratic filter equation [closed]

I am trying to calculate input impedance of a multiple feedback low pass filter. What I need is the symbolic expression as simple as possible so that later I fill in the values and get the impedance ...
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1answer
247 views

Remote EEG detection / reading

I recently noted that Philips, Accenture, and Emotive grouped together to create a proof of concept that would assist ALS patients to gain greater control of their lives through brain, voice, and eye ...
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1answer
319 views

Are there any radiation emitted from the cameras? [closed]

Do modern video cameras emit any kind of radiation? If so, what range of frequencies they have? I was wondering if we can detect any radiation so any help regarding detection will also be appreciated. ...