Questions tagged [electronics]

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(https://electronics.stackexchange.com/) SE site.

Filter by
Sorted by
Tagged with
4
votes
3answers
941 views

number of electrons my laptop uses in a second

in order to confirm whether I understand the relation ship between amps, columbs and electrons I decided to try out the following. my laptop adapter's label reads 3.34 amps. I assume that: amps are ...
3
votes
3answers
13k views

What is a virtual ground?

What is a virtual ground? I would like to know what it is.
3
votes
2answers
1k views

Why two separate batteries in a circuit don't work? [duplicate]

If electrons move from the negative side to the positive side in a battery(thus creating electricity when they flow), why doing the same circuit with two separate batteries doesn't create electricity? ...
3
votes
4answers
4k views

Would connecting p-type and n-type semiconductors work as a diode?

If we placed p-type and n-type semiconductors close enough to be touching (see fig. 1), would this arrangement work as a diode? ...
3
votes
2answers
9k views

Why are there two quasi Fermi levels and only one Equilibrium Fermi level?

I am reading a book and I'm trying to understand the concept of quasi Fermi levels. For example, A steady state of Electron Hole pairs are created at the rate of $10^{13}\ \mathrm{cm}^{-3}$ per $\...
3
votes
1answer
1k 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 ...
3
votes
1answer
208 views

Why do I see different color sparks from the 2 pins when I plug an appliance in a socket?

I plugged in the charger of my laptop into a socket, which I have done a lot of times but this time, I noticed a strange thing. When the contact was made between the pins of charger and the socket, ...
3
votes
1answer
67 views

What is the source of high pitch noise made by Polaroid instant cameras?

I've been wondering for a long time now, what is the source of that faint high pitch noise that is made by old Polaroid instant cameras. For the reference, the sound at 0:24-0:30 in this video. I ...
3
votes
1answer
50 views

Sound an amplifier makes when you plug / unplug a cable [closed]

When you plug, unplug or even touch a jack cable of an aplifying system with speakers, one can hear a low-pitch sound that is of roughly always the same frequency, which does not seem to depend on the ...
3
votes
3answers
209 views

Calculation For Thermal Conductivity [closed]

Total newbie here way over my head on a project I'm working on. I need to protect some electronics while they are inside an injection mould of liquid latex that measures 180 degrees celsius. The ...
3
votes
1answer
1k views

Why is 2-terminal sensing less accurate than 4-terminal sensing if the internal resistance of leads is known?

I have a pretty good understanding of 2-terminal vs. 4-terminal (kelvin) sensing measurements. I understand that in the 4-terminal measurement, current is supplied by 2 terminals that are separate ...
3
votes
5answers
3k 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 useless,...
3
votes
3answers
117 views

Real silicon atom structure?

Text books say that a pure silicon atom has four electrons in its outermost orbit. How do the scientists know it has four electrons?
3
votes
1answer
809 views

How diffusion and drift current in a PN junction get equal?

Let's consider a PN junction which is at zero biased voltage. Once the junction is formed charges are diffused across the junction and form the depletion region and stops further diffusion. So no ...
3
votes
1answer
37 views

Is there a limiting frequency for transformers due to the time required to establish the magnetic field?

I was just wondering if there were some upper frequency at which a field would not fully form in a transformer and the output would be clipped.
3
votes
4answers
421 views

Can Zener Breakdown be converted to Avalanche breakdown?

Wikipedia says: The Zener effect is distinct from avalanche breakdown. Avalanche breakdown involves minority carrier electrons in the transition region being accelerated, by the electric field, to ...
3
votes
2answers
1k views

Thevenin theorem and its proof

In the proof of this theorem a test current source is attached to the terminals of a network called $N$. We want to know the equivalent of network $N$. Then we calculate the potential at this terminal ...
3
votes
1answer
251 views

Why is responsivity quoted as a figure of merit?

Lately I have been investigating the physics literature on proposed photosensitive electronic devices made of graphene. Often I see responsivity values quoted as if they suppossed to impress, and ...
3
votes
1answer
1k views

Explanation of the Graetz circuit

My knowledge of circuits is pretty rudimentary and I've never really understood circuits, so I'm having trouble with the concept of Graetz circuits: When you register the voltage on the resistor R on ...
3
votes
1answer
85 views

Internet - mobile phone vs wifi

wifi cost me like 30USD while mobile internet 10USD, I thought to save this monthly bill by purchasing a mobile-phone-router. The only thing that blocks me from that is radiation. I'm far fetched ...
3
votes
1answer
414 views

Power consumption of a qubit?

I keep hearing “A quantum computer will consume so much power that it'll need a dedicated power plant.” I'm trying to find literature to back this up. I would love to get an estimate for the ...
3
votes
1answer
55 views

How can I use a pulse generator to simulate charge collection in multi-wire, proportional ionization chamber?

I'm performing tests of the detector's breakout electronics. These are printed circuit boards that will take signals from inside an ionization detector to the rest of the data acquisition apparatus. ...
3
votes
1answer
110 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 ...
3
votes
3answers
590 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 ...
3
votes
2answers
1k views

Why do batteries become weaker

I was thinking about my phone (Sony Xperia Z2) and when I put it to charge and remove it, the phone says "Please remove the charger, to save battery life," which is very intuitive question for a ...
3
votes
0answers
388 views

Continuous-time loop computer for NP problems? [closed]

In NP problems we can cheaply (polynomial time) test if a given input is satisfying, but the difficulty is that there is an exponential number of possible inputs - the question is if e.g. there is a ...
3
votes
1answer
735 views

Why is an $RLC$ resonance curve asymmetric? [duplicate]

When I was measuring the current with varying frequency of an series RLC circuit, I noticed that the graph produced is asymmetric: Is there any reason for this? (inductance=8.29mH) The Q-factor is 2....
3
votes
1answer
89 views

Can you get a better signal to noise ratio by connecting multiple microphones in series?

From my very basic understanding of microphones, they generate a tiny bit of electricity as the membrane moves, this is the signal. It would stand to reason then, that if I connect a bunch of ...
3
votes
0answers
198 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 ...
2
votes
3answers
3k views

Why doesn't the Earth's magnetic field affect electronics?

Why doesn't the Earth's magnetic field affect electronics in the same way that a magnetic field affects/exerts a force on a wire with a charge at a perpendicular angle? Isn't that why electric motors ...
2
votes
2answers
284 views

Capacitor in a superconducting circuit

Assume we have started a current in a closed circuit which only includes a capacitor. No inductor. For example by having a battery initially, disconnecting and and reclosing the circuit. For a ...
2
votes
2answers
235 views

Mechanical work to required battery power

I have a very practical question where I've calculated the mechanical work needed by a simple mechanical system by solving the line integral $W = \int_C \ F \ dx$. However, since I have a black spot ...
2
votes
1answer
51 views

Photomultiplier pulses only at first few channels?

I have an old Hamamatsu PMT, and I have a scintillator that can detect neutrons, gammas, alphas. But no matter what source I use, I'm only seeing counts at the first few channels (up to about the 15th ...
2
votes
2answers
435 views

Why a tunnel diode (TD) is called a diode?

Traditionally, a diode is a 2-terminal device that limits current to flow in one direction, i.e. a rectifier. But a "tunnel diode", according to wikipedia, is not rectifying: In the tunnel diode, ...
2
votes
2answers
9k views

Why do circuits work so fast?

Drift velocity (explained to me as how fast the electrons are moving) is really slow. My book says the electrons move at around 10 mm/ s. If electrons move so slowly how do circuits work so fast? If ...
2
votes
2answers
388 views

Is it possible to record the 'blue air" effect when a core goes critical?

I've been studying about radiation, and I saw something called the Demon Core. Apparently, it was a core that was under experimentation by the government in Los Alamos to see the exact point at which ...
2
votes
4answers
949 views

what could generate a high-pitched whine in electronics where the frequency depends on the current?

So I was operating a Laue machine recently which generates x-rays and fires them at a sample, and I noticed that there was a high-pitched whine coming from the instrument (nothing abnormal, just ...
2
votes
2answers
61 views

What makes quartz oscillators vibrate?

I understand that the principle behind it is piezoelectricity and electrostriction (inverse piezoelectricity), but how does one make the crystal vibrate? The only thing I can think of is using an ...
2
votes
1answer
201 views

Photomultiplier/ voltage divider troubleshooting

I have a Photonis XP5301 PMT to use for fast neutron detection (detector optically glued to the PMT window). I can't quite figure out why its not producing a spectrum. First of all, I have multiple ...
2
votes
1answer
1k views

Main cause of self-charging of unshorted capacitors?

In the lab, we keep all of the high voltage capacitors shorted when not in use, and rightfully so. They tend to spontaneously charge when left for some time and become extremely dangerous. while the ...
2
votes
1answer
199 views

Why Microchannel Plates can be operated only in vacuum?

Why it is said that the Microchannel Plates can be operated in vacuum? What is the maximum pressure in which it can be operated? Also, while it is not operating, should it be kept in vacuum? Is this ...
2
votes
4answers
9k 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 ...
2
votes
2answers
4k views

What is the difference of the two stable states of a Flip-flop?

In electronics, a flip-flop or latch is a circuit that has two stable states and can be used to store state information. [...] Flip-flops and latches are used as data storage elements. Such data ...
2
votes
1answer
83 views

Why are the active noise cancellation headphones subjectively better in reducing “periodic” noise?

According to experience of mine and of my friends using active noise cancellation headphones, the technology is much more efficient in reducing "periodic" noise, such as humming of jet engine, fridge ...
2
votes
2answers
170 views

Science of Daisy-chaining [closed]

As everyone knows daisy-chaining power strips is very bad and dangerous. But could someone tell me why it's dangerous from a physics standpoint? (i.e. its effect on voltage, current, etc)
2
votes
1answer
56 views

What happen to organic solar cell when applied electric field? [closed]

For example, I have a PTB7:PCBM organic solar cell. I applied electric field in forward basis. Will it contribute to increase charge separation? Then, if I do in reverse basis, what will happen to ...
2
votes
2answers
159 views

Why don't radio waves ruin electronics?

Out of curiosity, I estimated the voltage amplitude for typical visible light. Wikipedia says that sunlight hits the earth at about $1000 W / m^2$. The intensity of an electric field is given by $$I =...
2
votes
1answer
274 views

What happens if a PMT (photmultiplier tube) is run below its operating voltage?

I have this Hamamatsu PMT that says its operating voltage is 1500 V. However, it has serious electronic/background noise at LLD=0 at that operating voltage. If I lower it down to about 1.02 KV, noise ...
2
votes
4answers
1k views

What is the potential difference across a disconnected diode? [duplicate]

I think potential difference across disconnected diode should be zero but how? the last graph tells that there is a potential difference between the two ends of a diode. then how can be it zero?
2
votes
1answer
311 views

Why does a field-effect transistor (FET) with wrap-around gate work at all?

In the recent years several publications have presented field-effect transistors (FETs) that are based on semiconductor nanowires with a gate electrode that is wrapped around the whole nanowire ...