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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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 useless,...
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2answers
479 views

Problems in the modern semiconductor/electronics technology?

From what I have read, the problem with modern semiconductors/electronics seems to be quantum tunnelling and heat. The root of these problems is the size of the devices. The electrons are leaking out, ...
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1answer
33 views

How would you read memristor data?

According to many experts; memristors have the potential to change and drastically improve data storage and processing power of computers. But there is one small thing that doesn't fully make sense to ...
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1answer
67 views

Why does small change in Base current causes a larger change in collector current in case of transistors? [closed]

Why does small change in the base current causes larger change in the collector current. That is say if I increase the base current buy a small amount why the collector current increases by a very ...
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6answers
258 views

Current when resistance is 0

A short circuit has $\rm 0$ resistance. We use Ohm's Law $\rm V=IR$. If $\rm R=0$, then $\rm V=0$. Doesn't this mean $\rm I$ can theoretically be anything? Thus $\rm I$ can be like $\rm35A$ for ...
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1answer
34 views

Effect of charge on electric circuit in free space

Assume I put some electronic device, a laptop for example, in free space. Now add electrons to the object. It will become progressively more negatively charged. At what point will the laptop (or ...
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2answers
105 views

Shining light (of a particular frequency) on an insulator to make it into a conductor

Recently I read about band theory of solids. The energy difference between valence band and conduction band determines the conductive property of solids. Suppose I take an insulator and shine it with ...
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2answers
67 views

Why are holes (in a semi conductor) regarded as particle?

Can I say that holes in a semiconductors are treated as current-carrying conventional direction ?
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1answer
2k views

Calculating Boltzmann constant using semiconductor

My task from the latest laboratory exercise in physics is to calculate Boltzmann constant from known temperature, current and voltage. We were given this circuit: By changing the resistor value, I ...
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2answers
146 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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1answer
610 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
172 views

What do I get when measuring on top of metal/insulator/metal by kelvin probe?

I am using a macroscopic Kelvin Probe for work function measurement. There's one confusing condition. If I measure a trilayer thin film stack with a structure of ITO(bottom)/PMMA(100-200nm)/Al(top), ...
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1answer
151 views

How does rust behave as a PN junction?

Reading about old-fangled radios the reference quoted below indicates it was/is possible to use a rusted razor (or perhaps any similar thin corroded metal strip) as a detector. Some resourceful GIs ...
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1answer
58 views

The width of the space charge region in a pn-junction

Given a pn-junction as in the picture below. Which quantity determines the width of the space charge region? Or in other words, why don't the electrons in the n-doped region wander towards the ...
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0answers
20 views

Can seebeck chips be used to extract Peltier chip waste heat?

I understand that a problem with employing the Peltier effect for the purpose of cooling is that it produces a significant amount of heat on the hot plate. But why don't we use seebeck optimised chips ...
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0answers
36 views

How to control a dc motor? [closed]

I am in 8th standard and I am doing a project on 3d printing pens. I want to know how to control a dc motor, so that when I press a button it should increase its speed gradually till it reaches its ...
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90 views

Materials for use in a solar cell

In a solar cell, photons of the incident sunlight supply energy for excitation of electrons - a process which generates electron-hole pairs which can move under the influence of the electric field of ...
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0answers
13 views

Have the BaF2 scintillators a strong correlation with the alimentation current that cause the shifting of the centroids in the distribution?

In gamma gamma correlation I suspect the presence of systematic error maybe caused by a non optimal alimentation voltage according to someone there is a quadratic correlation between centroids ...
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0answers
131 views

Piezoelectric effects of naturally shaped quartz crystal for maximium Q?

Background Based on helpful comments and links here and also from my question on the electronics stackexchange, I have learned that the quartz crystals are nature's transducers of energy, allowing ...
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0answers
110 views

Really Struggling in electronics. What to do? [closed]

This is my first post so please go easy on me. Okay. Let me introduce myself. I am a first year undergrad CS student who has to study basic electronic course for one semester. As the title says, I am ...
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0answers
334 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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3answers
460 views

If we connect a block of p-type semiconductor only to a positive terminal, will it become positively charged?

Connect the positive terminal of a battery to a piece of p-doped semiconductor, say, silicon doped with boron. Will the terminal pull electrons out of the doped silicon, or equivalently, inject holes ...
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3answers
1k 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
83 views

Can we have electronics with charge carriers OTHER than electrons?

Ions perhaps? Or other elementary particles with charge?
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2answers
103 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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1answer
115 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
386 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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2answers
134 views

Time delays in live TV talk shows

Quite often I observed that whenever a caller participates in a live TV talk show, there is delay of time to respond a particular question asked by the compère of the program. This delay is due to the ...
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2answers
346 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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2answers
574 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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5answers
9k 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
113 views

Why is $np$ always equal to $n_i^2$?

For you guys who studied semiconductor physics must be familiar with the equation: $$np=n_i^2$$ I can understand why this is true for the intrinsic case (the broken bonds would always provide ...
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1answer
88 views

What's the purpose of capacitors in parallel

In my school textbook it is written that the capacitor acts as a filter, that is, it decreases the fluctuations in the potential difference across the load. But since all the components are ...
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1answer
200 views

why is I-V characteristics of a solar cell drawn in the 4th quadrant?

My book says because a solar cell does not draw current but supplies it to the load. I don't quite get the explanation. How is it related?
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2answers
35 views

Semi conductors (holes and electrons)

The following relation is mentioned in my text book for semiconductors in thermal equilibrium. $$n_e ×n_h = n_i^2$$ $n_e$ stands for the number of electrons. $n_h$ stands for the number of holes. ...
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1answer
107 views

Textbook recommendations for electrical circuits and electronics?

I'm a junior physics major focusing on theoretical physics. I didn't take any courses in electrical circuits or electronics (though I did take E&M). Recently I started feeling that this is a ...
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3answers
115 views

How does the tuner really work in a crystal set?

I would like to know how and why the tuner works in a crystal set radio. I already know all the theory and the "formal definitions" (this creates a resonant circuit which responds to an alternating ...
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2answers
50 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
148 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
111 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
5k 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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2answers
387 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
47 views

Equivalent DC circuit with charged conductors

I am trying to find equivalent circuit for a circuit composed of interconnected capacitors when isolated pieces of conductor may carry nonzero electric charge, and I have been struggling with this ...
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1answer
253 views

Half wave rectifier at high frequency and small amplitude ac signal

This is the picture taken from my oscilloscope where I was just checking how a standard half wave rectifier properties. The yellow one is input signal of frequency 20.5KHz and peak to peak value is ...
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4answers
240 views

Voltage - Energy drop

I'm having a hard time understanding the nature of voltage and am hoping you guys can help. The main issue is the concept of the voltage drop. Take the following circuits : In regard to the first, ...
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1answer
80 views

About the combination of two signals with capacitors

Here is a link of an article I've been reading. http://www.analoguehaven.com/moog/thereminblack/hotrod.pdf In page 4 there is a circuit schematic. Notice there is a part called variable pitch ...
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3answers
172 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
339 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
509 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
27 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 + \...