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.

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56
votes
3answers
9k views

Is there a physical limit to data transfer rate?

Is there a physical limit to data transfer rate (e.g. for USB $3.0$, this rate can be a few Gbit per second)? I am wondering if there is a physical law giving a fundamental limit to data transfer rate,...
23
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5answers
22k views

What's the physical meaning of the imaginary component of impedance?

As you know, impedance is defined as a complex number. Ideal capacitors: $$ \frac {1} {j \omega C} \hspace{0.5 pc} \mathrm{or} \hspace{0.5 pc} \frac {1} {sC} $$ Ideal inductors: $$ j \omega L \...
16
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5answers
35k views

How does power consumption vary with the processor frequency in a typical computer? [closed]

I am looking for an estimate on the relationship between the rate of increase of power usage as the frequency of the processor is increased. Any references to findings on this would be helpful.
16
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1answer
2k views

What's the size of the smallest possible pixel size that can be physically detected using an electronic device?

For a given wavelength $\lambda$, is there a limit on the size of the sensor pixel, regardless of the optical equipment attached to the sensor or the nature of the censor?
14
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2answers
210 views

Dust patterns inside electronic product - what causes this? [duplicate]

(Note: another similar question from a few years ago yielded nought but speculation. I have at provided some detailed observations in the hope that the community can come up with something rigorous as ...
12
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3answers
3k views

How do Zener diodes maintain the potential across their terminals?

My physics book has a topic about Zener diodes being used as voltage regulators in the reverse bias. Well, I'm curious to know how does a Zener diode maintain the potential across its terminals after ...
11
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3answers
13k views

Is it viable or possible to make your own transistor?

Just wondering if it is possible/viable to construct your own transistor, not small like todays, but the same scale as the one created at Bell Labs.
11
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1answer
2k views

Why do you only hear high frequencies when a microphone is near its speaker?

The phenomenon I'm talking about is positive feedback, as known from control engineering: when the microphone is too close to its speaker, it can "hear itself", so the signal will be infinitely ...
10
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4answers
3k views

How electrons move so fast in a electric circuit?

Whenever we switch on a bulb......it takes almost no time to glow up.....But we know that the atoms of a solid are tightly packed and there is a very little space between them. So how the electrons ...
10
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6answers
21k views

What would be the effective resistance of the ladder of resistors having n steps

I'm a tutor. This is a high school level problem. In high school, every one have might have solved a problem of effective resistance of a ladder of resistors having infinite steps. Now the problem is ...
10
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3answers
39k views

Why can electricity flow only in one direction through a diode?

A few days ago I was soldering a small thing which contained a diode, a battery and some other useless things. Unfortunately, I soldered the diode reversed and it didn't work. When I reversed it ...
9
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3answers
2k views

Verifying radiation measurement smart phone applications

I've stumbled upon a strange class of Android applications lately. (And I'm sure such applications are available for other platforms too.) These apps claim the ability of detecting radiation. The ...
9
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1answer
389 views

Why do I hear voices when I touch my turntable needle?

So I was trying to figure out the reason why my old (and probably sufficiently damaged) needle on my phonograph (turntable) was not working like it was a little while ago. With my headphones on, I ...
8
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1answer
10k views

How does a digital radio tuner work?

I believe I understand how tuning a radio with an analog tuner works: turning the dial physically changes the length of the antenna, which determines which broadcast wavelength will resonate in the ...
8
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3answers
10k views

Pn junction voltage drop?

This image from wikipedia, explains that there occurs a potential drop across a pn semiconductor junction, and an electric field confined to the depletion region. I already know the reason for the ...
8
votes
3answers
226 views

Is there a physical limit to memory reading and writing speed?

Is there a limit to the speed at which a memory, quantum or classical, can be read or written into? I've seen this interesting question : Is there a physical limit to data transfer rate?. Here I'm ...
8
votes
1answer
24k views

Why does it spark when I push a plug in the electrical socket?

When I slowly push a plug into the electrical socket I can often see sparks. Can anybody explain why? Can this be possibly harmful for the devices I plug in?
8
votes
2answers
966 views

Would a major electromagnetic pulse (EMP) leave most cars operable?

According to C. Davis of the Ask a Prepper blog, after a major electromagnetic pulse: Most electronics will be fried beyond repair and it will be years – in some cases decades – before anyone is ...
8
votes
1answer
398 views

Is radar-style 'pulse coding' (stretch, amplify, interact, and then compress) used in the optical domain?

Chirped Pulse Amplification (CPA) is an optics technique for producing short laser pulses at intensities which are high enough that the gain medium would destroy itself through nonlinear phenomena ...
7
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4answers
7k views

What are the effects of cosmic rays on consumer electronics? [closed]

When electronics/computer companies design a new chip, processor/ memory card/ or a solar cell, do they study the effect of cosmic rays on such electronically sensitive materials? If not, why not?
7
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1answer
4k views

How do Zener diodes survive the breakdown during reverse bias?

My highschool textbook states that Zener diodes are a special type of diode which is made of highly doped p and n junctions, and which can survive reverse bias - unlike normal diodes, which get ...
7
votes
1answer
109 views

Why is contact resistance proportional to $\frac{1}{\sqrt{F}}$ not $\frac{1}{F}$?

See pages 13-15 in "Electrical Contacts: Principles and Applications" for reference. Imagine the following system: Two flat, but rough, surfaces of the same finite area $A$ being brought together. ...
7
votes
1answer
317 views

Cell phone ring made nearby speaker to create strange noise [duplicate]

I was sitting on my chair in office when my cell phone rung. Somebody was calling me, so there was a caller tune which was played. But then I realized my speakers were producing strange sound when ...
6
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4answers
6k views

Do resistor-based fan regulators save no power at all?

I have heard that the traditional resistor-based fan speed regulators are inefficient. In fact, I have noticed that such regulators tend to get hot when the fan is set to low speed. However, does that ...
6
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2answers
1k 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 ...
6
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2answers
2k views

How did the Bardeen-Brattain point-contact transistor work?

I've been trying to understand how the Bardeen-Brattain point-contact transistor worked. The point-contact transistor uses Schottky barriers (metal/semi-conductor junctions), so under what conditions ...
5
votes
3answers
361 views

How does radiation degrade mechanical parts and electronic devices?

I'm running out of places to look (lots of Googling, SE, [articles and books are too specific and never give a good overview]), and yet I am still unsure about how exactly radiation can degrade ...
5
votes
1answer
1k views

What is meant by phase coherence of electrons?

I came across a term "phase coherent electron devices" in the book Condensed Matter Field Theory by Atland and Simons. What is meant my phase coherent electrons (coherence is a term generally talked ...
5
votes
1answer
11k views

Why does the monitor make a cracking noise?

After switching off the monitor, there's a single crack after a while. I wonder where exactly it comes from. I know that this is normal and not an indicator of being defect. This sound is also not ...
5
votes
4answers
42k views

Working of a p-n junction diode when forward biased

If p-type semiconductor and n-type semiconductor of a diode are equally doped, and if the diode is forward biased, then holes will move toward the n-type semiconductor and electrons will move toward ...
5
votes
2answers
3k views

Why are only Group III & V elements used for doping?

Only group III & IV are used for doping in elemental semiconductors like Si and Ge, why can't other groups be used instead?
5
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2answers
168 views

Layered CMOS structure question

I am trying to understand the workings of a CMOS image sensor. I understand that increasing wavelength results in an increased penetration depth in the silicon often used in CMOS image sensors. What ...
5
votes
3answers
143 views

Do donor atoms leave holes?

I was reading text about n-type doping and it said: 'Such impurities are called donors for they donate electrons. Notice that in this case, no hole is created in conjunction with the creation of a ...
5
votes
1answer
171 views

A question about Memristors

A question about memristors: These semiconductor entities have been defined in terms of magnetic flux leakage, and a non-linear relationship to the electric charge that has flowed. In essence, the ...
5
votes
1answer
160 views

Cosmic Ray Detection | Florescent Light Bulbs

Main: Can cosmic rays be detected through florescent bulbs? Can you push an AC current through a florescent lightbulb tube and measure the current draw and voltage spikes to detect cosmic rays? Is ...
5
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0answers
768 views

Smallest minimum feature size possible for transistors printed by photolithography

I'm doing a project about Moore's Law, one of the subtopics I've come to is photolithography. The way I understand it is that the MOSFET transistors are currently printed on a silicon wafer by ...
4
votes
1answer
851 views

Can electrons move through vacuum?

I studied that electronics is the branch of physics which deals with the practical applications of moving electrons through vacuum, semi-conductors and gasses. Can electrons move through vacuum?
4
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2answers
2k views

Why does sticking a knife into an operating toaster give you a shock?

I understand why sticking a knife into a toaster produces an explosive phenomenon. It completes the conductive connection between the two holes in the electrical outlet and the 250 volts or so that ...
4
votes
1answer
46k 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 courtesy ...
4
votes
5answers
22k 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 ...
4
votes
2answers
1k views

Does van Eck phreaking really work, or is it an urban myth?

Van Eck phreaking, the ability to reconstruct distally the text on a CRT or LCD screen using the leaking em from the target computer, was in the news about five to ten years ago. It is talked about as ...
4
votes
2answers
572 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 ...
4
votes
6answers
20k 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 ...
4
votes
1answer
85 views

Receiving AM radio through household wiring

A friend's post on FB made me recall a similar situation. In his case, his IR-linked headphones now play a local AM station at very low volume whenever he's near an electrical outlet or switch in his ...
4
votes
2answers
106 views

Why does a hole moves from one atom to another?

I know that in p-type semiconductors there are holes i.e the absence of electrons. What I can not understand is why electron from neighboring atom tends to fill that hole leaving a hole behind itself? ...
4
votes
1answer
816 views

What does a MEMS gyro measure during off-axis rotations?

I've been working with MEMS gyroscopes in hobbyist projects for years—but it's recently come to my attention that I don't have any principled understanding of what rotation rate measurements ...
4
votes
1answer
2k views

Turn-on delay time for Laser diode

Do you know any simple explanation on the reason why the turn-on delay time on a laser diode is reducing while we increase the bias current? Turn on delay,is the time that the laser needs from the ...
4
votes
2answers
3k views

lifetime of a PN junction in a diode

diodes are made of silicon, which have been enriched in phosphorus and boron to create the PN junction. Since the electrons are always going in the same direction, from N to P in the junction, I was ...
4
votes
1answer
57 views

Different Color Intenensities from simple ON/OFF RGB subpixels

I recently got interested in electronic paper. One design that I liked was the one from Mirasol: https://en.wikipedia.org/wiki/Interferometric_modulator_display However, what I don't understand, is ...
4
votes
0answers
120 views

What is the physical reason behind the negative differential resistance (NDR)?

As you know, there is an effect called negative differential resistance in some electric devices and materials, but I could not find any article or book or any other reference to talk about the ...