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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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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. ...
8
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2answers
975 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 ...
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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 ...
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0answers
42 views

Determination of optimum gain for neutron detection system?

I have a Hamamtsu PMT that operates at 1500V. I've used different gains, and got different curves for each (shown in figure, x-axis is channel number, y-axis is number of counts). How does one ...
0
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1answer
31 views

Effect of near zero temperature in ac transformer

Would there be any variation in the usual ac transformer behavior if one of the coils (namely, the primary coil) - or both - was made of a superconducting material (i.e: lead) and cooled to near zero ...
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0answers
313 views

How do ferrite beads work?

How do ferrite beads, those small cylinders found on cables, work? I understand that they are meant to filter out high frequency noise. I also understand what a low-pass filter is and how an inductor ...
4
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0answers
121 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 ...
2
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1answer
199 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 ...
-3
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1answer
791 views

Can a mobile phone emit gamma rays? [closed]

I heard that inside the battery of mobile phones (but also of other electronic devices) can happen quantum leaps that cause the emission of gamma rays photons. Is this phenomenon really possible?
14
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2answers
211 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 ...
1
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1answer
57 views

How is there a -0.7V charge gap in a diode?

According to physics books, the negative charge in the N-type and the positive charge in the P-type semiconductor causes some electrons and holes to cross over to the other side. Then, apparently, the ...
3
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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.
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2answers
97 views

Capacitor Discharging through a fixed resistor

When a capacitor discharges, the pd across it goes from V0 to 0 in a given time. But when you look at the pd across the fixed resistor, this too decreases from V0 to 0. So we can say Vcapacitor=...
1
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1answer
106 views

Why is the emitter current of a common emitter slightly greater than the collector current?

I'm trying understand where electricians came to agreement that Ie = Ib + Ic. I know that the base of a NPN transistor is very thin, allowing electrons to flow through to the collector which explains ...
0
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0answers
41 views

Could ballistic electron transport be used for transmission lines and undersea cables?

Ballistic conduction, from what I know, resembles superconductivity sans the Meissner effect. But unlike superconductivity it can occur at room temperature.Has there been any R&D in the use of ...
0
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2answers
60 views

What happens if an electric charge is run through a resistor on both ends? [closed]

For example, if 2 wires connected in parallel have a resistor put between them, how would you calculate the effective resistance of this circuit?
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0answers
38 views

Electronics in high level of radioactivity (Fukushima example)

In this website is stated that robots that were sent to Fukushima plant after the disaster were made obsolete by high levels of radioactivity. Apart from the obvious fact, that because of nuclear ...
1
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0answers
157 views

Which coil configurations transfers the most magnetic flux?

So i'm working on a home project that involves magnetic coupling. I was wondering, of the two configurations described bellow, which one would should allow the secondary coil to receive the most ...
1
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1answer
257 views

What is the physical quantity which makes a Reed switch open or close?

I would like to generate the activation map of a Reed switch, similar to the following: Using a magnetic finite element modeling software such as FEMM. Assuming the Reed switch closes for X Ampere-...
0
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1answer
35 views

The best resolution that a 7 bit A/D convertor with 5 V full scale can achieve is …mV [closed]

Can anyone please tell me what should be its answer?
0
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1answer
203 views

Approximation for deriving I-V characteristic of pn junction

I am struggling with some approximation while deriving I-V characteristic of a pn junction. Let's consider a quasi-neutral region on the n side of pn junction. There are four current components as ...
2
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1answer
73 views

What is the difference between Si pixel and Si strips used in CMS Inner tracker at CERN?

What is the difference between Si pixel and Si strips used in CMS at CERN? Both are used for tracking and as the CERN website mentions, they are also based on the same working principles. Or are they ...
5
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1answer
165 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 ...
0
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1answer
267 views

Semiconductors ->Transistors npn and pnp

I have had a tough time with semiconductors, I cannot understand the working of a transistor in saturation, as a switch, and also the cases as to when which part is forward biased, I also tried google ...
0
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0answers
93 views

Building a particle accelerator with Cathode Ray tube

I was thinking of simple ways to create a particle accelerator and I thought of using a cathode ray tube and sending electrons through it. I would have to apply a lot of voltage so the electrons could ...
3
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4answers
417 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 ...
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2answers
4k views

Why is it that potential difference decreases in thermistor when temperature of circuit is increased?

Why is it that potential difference decreases in thermistor when temperature of circuit is increased? From my understanding when temperature increases, there are more free electrons ($n$) so according ...
1
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0answers
57 views

Could we use spin in transistors?

can we make a transistor which uses magnetic field? the idea is to put a magnetic material between two magnetic materials which have a fixed magnetization direction. We give the middle material a ...
-2
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1answer
381 views

Question on Fuse Placing [closed]

Please answer Q.no 11 (where should the fuse be placed and why?)
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0answers
916 views

Why is the conduction band of Si not monotonic?

A typical band structure of silicon is shown in the picture. If we consider a subband of the conduction band within the first Brillouin zones, we can clearly see that this subband is not monotonic. It ...
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 ...
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0answers
21 views

What kinds of materials are useful for field emission vacuum tube cathodes?

I've read that graphene has been used for small scale field emission but what about on a much larger scale? For example what are the "cold cathodes" of FEM miscroscopes made up of?
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2answers
68 views

light point and photosensor

When a laser pointer is pointed at a screen or at a target that spot can be detected because the laser beam falls on the target and bounces back and then is detected by a photosensor. But, what if it ...
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 ...
-1
votes
1answer
645 views

A problem in solving a simple electronics circuit [closed]

In the circuit given below are 5V and -2V supplies connected in parallel to each other? Is input at upper terminal of op amp 3V? If not 3 then what? please elaborate these three points. I am trying ...
1
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1answer
621 views

The inside of a variable resistor (potentiometer)

I've come across a past paper question which asks to describe the inside of a dial pot potentiometer. I've been reading through this page which describes it very well, but I still have a few ...
3
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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 ...
2
votes
1answer
319 views

Memristors: how are memristors modeled in terms of impedance?

How are memristors modeled in terms of impedance? I have been searching the net for memristors, but could not get much of an idea. I'm not interested in how memristors are made (by combining ...
1
vote
1answer
52 views

Can the electrical signal in the Electromagnetic wave be rectified?

The radio waves are received through the antenna and in that case, we obtain the electric signal. Could that electric signal be rectified?
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? ...
0
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0answers
44 views

Silicon purity and electronic feature density

During development of an integrated circuit it is my understanding that you require a silicon purity of 99.99999999%. Has this always been the case? In 1971, had the first commercially available ...
0
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1answer
94 views

Bandwidth and gain of operational amplifier

Please explain the relation between bandwidth and gain of op-amp. I have learned that negative feedback could reduce gain and increase bandwidth of an amplifier. Since gain= Vout/Vin, I understand ...
1
vote
1answer
202 views

Geiger Counter Electronics Dead Time

In essence, I am working with an old (1960s) Geiger-Muller tube and a set of counting electronics, including an amplifier. Unfortunately, I don't have access to them for the next month or so, due to ...
3
votes
3answers
208 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 ...
0
votes
2answers
341 views

Can we prove “Lumped element model” mathematically?

Maybe this question is both in the fields of engineering and physics. As it seems the electrical quantities like Resistance, Capacitance, Inductance, and so on are quantities we assign to distributed ...
1
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2answers
973 views

What causes reverse leakage current in an LED?

I've read it can be due to 'intrinsic semiconductor conduction' and surface conduction. The LED I am looking at is InAs, which is apparently prone to surface conduction. I have tried out what these ...
0
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1answer
113 views

Simple proof of equation for current through a pn junction directly polarized

I've attending an introductory course in semiconductor physics and I am having some difficulties in find a simple derivation of the equation: \begin{equation} I=I_s \left( e^{\frac{V_D}{V_t}} -1 \...
1
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0answers
114 views

What are the advantages of using a hetero-junction in Tunneling Field Effect Transistors (TFETs)?

What are the advantages of using a hetero-junction in Tunneling Field Effect Transistors (TFETs)? How is the heterojunction able to improve the Ion/Ioff ratio of a TFET?
0
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1answer
236 views

Photodiode circuit

I'm stuck at the following question: At peak intensity, the photo-diode outputs a current of $I=34\;\mathrm{\mu A}$. At that point $u_0$ needs to be $5\,\mathrm V$. Pick a value for $R$ that ...
2
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1answer
118 views

Accumulation Region of an NMOS

I'm trying to get a better understanding of how the NMOS works when a negative voltage is applied to the gate. So I currently understand that the $P^-$ substrate is lightly doped with such a ...