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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Why is the observed voltage 5V when the power supply is 18V? [migrated]
I am building a headlight driver circuit for my solar car team at school. The circuit uses transistors to drive the headlights and an 18V power supply. My HIGH and LOW signal is a 5V signal and 0V ...
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RF signal from Collector of Transistor [closed]
i creates a Radio an AM transmitter.
with the AM Collector modulation mode (tipycal AM DSB WC).
IT WORKS WELL in Oscilloscope.
but the (((SWR))) Show low RF Signals. only a few mW. Should 10 Watts.
...
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1
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When NPN collector is left open, does whole "collector" current flow out of the base?
The common phenomenological explanation of the forward active transistor operation is (e.g. in case of a NPN transistor) that when the base-emitter junction is forward biased holes can diffuse from ...
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How can DC current arise? [migrated]
I'm curious to understand the properties behind direct current (DC) and alternating current (AC) which started when reading the definition and several articles online that, "AC periodically ...
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Why do directional microphones have a high bass response at short distances?
In the audio field, it is taken as a given that directional microphones have a higher response at lower frequencies when the source is close to the microphone. Many directional microphones have a ...
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Deriving BJT transistor equation
Is it possible to derive the behavior of BJT transistors using semiconductor physics?
I have seen a derivation of PN junction behavior using some assumptions which was plausible to me but I had a ...
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If the electrons leaving and entering the battery per unit time is different during transient phase then how it's voltage doesn't change?
I am a high school student and I am very confused in how battery's and electricity actually works?
My question is: suppose we have an ideal battery, we know as soon as we switch on the DC circuit, a ...
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How does a large resistor in parallel with a thermistor affect the voltage-temperature graph curve?
I want to know whether my understanding of the thermistor being in parallel with a large fixed resistor is correct. There is another resistor in parallel with the thermistor but that is fixed and not ...
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Diode holes after battery is disconnected
When we connect n-type of diode with negative terminal of battery electrons flow from n-type to p-type and all the holes are occupied by electrons. I want to ask when we disconnect the battery does ...
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Actually, how does transistors work? [migrated]
I always thought I know how transistor works. At least before a friend of mine asked me an npn-switch under strange conditions and I'm confused now:
The drawing shows a normal npn-switch and the ...
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How can a camera capture the movement of light (in slow motion) if the electronics operate below the speed of light?
A while back I saw the MIT produced video where they show their camera capturing 1-trillion frames per second and show the light moving around a coke bottle in slow motion.
https://www.youtube.com/...
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What mechanism causes failure in a BJT when collector current is exceeded? [closed]
Does exceeding the rated collector current of a BJT cause the device to fail because it suddenly heats up very fast? Or is there some other reason?
If the reason is heat, I'm wondering if I can exceed ...
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Why doesn't passive cell balancing re-distribute electron charge?
I've done a lot of searching for an answer that's just eluding me. To put it simply, when series batteries are balanced using a passive balancing scheme (resistor and FET), why don't the electrons ...
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Failure distribution for florescent lights. Is the failure per unit time constant or does it increase with bulb age? [closed]
what is the distribution for the statistic:' time to failure' for florescent light bulbs. does the probability of failure per unit time stay fixed as the bulb ages, or does does it increase.
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Power equation in transmission lines [duplicate]
In transmission lines we increase the power to "reduce energy loss in the form of heat". Can someone explain exactly how and also I understand that we have to keep our power constant ...
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Zener Diode behavior under forward Biasing
I am facing difficulties in understanding the concept of zener diode and problems related to it.
My doubt is, In many texts I have read that if the input voltage is less than zener voltage, the diode ...
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How does a capacitor bottom plate get charged positive in DRAM?
So, I understand of the NMOS transistor work's here (at least I believe I do). Electrons are flowing towards the capacitor plate from the drain here. So, I don't get how the plate connected to the ...
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Are there any specifications required for the computer which would be connected to Computer Automated Measurement and Control (CAMAC)?
I wanna buy a computer to use with Computer Automated Measurement and Control (CAMAC).
Are there any specifications required for the computer which would be connected to CAMAC?
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What are the differences between PWM signals and digital signals [closed]
PWM (Pulse Width Modulation) is a way to handle analog devices and components with a digital output. What are the differences between those PWM and digital signals?
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Physics behind "nuisance trips" in a ground-fault circuit interrupter (GFCI) outlet due to switching off an inductive load elsewhere in circuit
I am working on rewiring my old house. All of the second-floor lights, switches, and outlets are on a single circuit from the breaker. I recently installed ceiling fans in the bedrooms with wall ...
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Obtaining $V_{avg}$ in derivation of Ohm's law using the Drude model [duplicate]
I am referring to Ashcroft/Mermin - Solid state physics.
After stating the assumptions of the Drude model,they go on to derive the Ohm's law starting with
j = -neV.
Where j is the current density, n ...
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Experimental realization of rectangular potential barrier
I was reading a QM book where they put the following figure aiming to explain how to realize experimentally a potential barrier/well. In the left (barrier) and right (well) plots they show a circuit ...
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Can the base of a transistor not be an intrinsic?
Can the base of a transistor not be an intrinsic semiconductor. I think doing so would reduce recombination.
Please explain me what would happen in that situation. I suggest that npn transistors are ...
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On a PV cell, why do electrons travel through the copper rather than through the PN junction?
thank you all for reading me!
I am currently reviewing the structure and working principles of a PV cell. I think I understand the following steps about how the PN junction is formed and what happens ...
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What provides the centripetal force for Cooper pairs flowing in a toroidal superconductor?
What provides the centripetal force for Cooper pairs flowing in a toroidal superconductor?
I asked myself this question, which led me to realize I also don't really know the answer to a more basic ...
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In cathode ray experiment, will cathode run out of electrons after some time?
If we are performing an cathode ray experiment will there be a time when cathode stop sending electrons or run out of electrons, something like that.
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Small resistance in parallel with with a large resistance. Does it affect the current in the larger resistance?
I'm a stupid high school student trying to understand domestic circuits. I've recently learned about the earth wire which reduces the value of current traveling through a person's body when they touch ...
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What exactly is voltage drop?
Ive been struggling with this question, I cant get an intuitive hang of it. I would like an explanation which focuses on the molecular level understanding of what happens inside the electrolyte and ...
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Why/If Cadmium Compounds are Used In Electronics Related to Light
So I've noticed that cadmium compounds show up quite a bit in electronics related to light. For example, cadmium telluride is apparently the most used material in solar panels aside from silicon. In ...
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Is this proof of the compensation theorem correct or not?
According to the compensation theorem, any impedance in a network can be replaced by a voltage source having zero internal impedance and an emf equal to the potential drop across the impedance.
Proof:
...
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Bending of vacuum level in semiconductor junctions
I am currently learning about semiconductor physics and have some problems understanding the band shifting which occurs at PN-junctions, heterojunctions or even metal-semiconductor junctions.
In most ...
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What is the "spring" and what is the "mass" in a loudspeaker system? [closed]
I've been reading about how speakers work and keep seeing that it is analogous to the mass on a spring system.
I'm trying to identify what is the "mass" and what is the "spring" in ...
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Average energy of a linear combination of several digital signals
I'm given a digital signal which is a LC of several known given digital signals and modulated by 4-bits:
s(t)= A·(b0·s0(t)+b1·s1(t)+b2·s2(t)+b3·s3(t))
Then, I'm asked to compute the average symbol ...
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How does a scintillator work? [duplicate]
I am trying to understand how a scintillator works.
Currently my understanding is this:
gamma radiation interacts with atom A (through photoelectric absorption or compton scatter) which produces a ...
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Fabricating an APD (Avalanche photo-diode) with a twist
Instead of one n-layer and three different types of p-layers, we have been given one p-layer and three different types of n-layers for fabricating an APD. In other words:
(a) Replacing the n+ layer ...
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2
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Why do silicon photodiodes respond to a wavelength range of 190-1100nm?
Silicon photodiodes respond to a wavelength range of around 190-1100nm (source: wikipedia). I understand that photodiodes function by having a photon of sufficient energy create an electron-hole pair ...
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Why are optic transistors faster if they use electrons also
Let’s say that this optical transistor used a detector which converts photons to electrons. We use those electrons to power some switch that lets light through when on and blocks it when off. Would ...
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Would a semiconductor in an optical fiber work as an optical transistor?
According to this website, the electron density affects the refractive index.
I planned on creating a doped semiconductor in an optical fiber. This meaning that I would dope the glass it reflects ...
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Why capacitor is taking much longer time for charging than it would by calculation?
I was studying the charging time of capacitor in a simple seriee RC circuit, with series resistance of 10 M-Ohm & capacitor of 10 microFarad. According to calculations, the should store ~63% ...
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Does higher Hertz mean a higher electric bill?
Suppose my electric utility is meant to provide power at 60 hertz, but instead it provides it at 61 hertz. Would my electric bill be higher? Assume I run the same appliances for the same amount of ...
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Determining the reverse breakdown voltage of a Zener diode graphically
I have been measuring the reverse bias IV characteristics of a Zener Diode BZX (2.7 V) at three different temperatures, -196.2 celcius (liquid nitrogen temperature), 22.0 celcius (room temperature) ...
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Are the $V$ in electronics and the $\phi$ in physics the same?
Is the electric scalar potential $\phi$ in physics the same thing as 'voltage', $V$, in electronics?
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Frequency response of ferrite filter
Why ferrite material only passes low frequency and blocks high frequency. I mean what's going inside this material which is leading to show such frequency characteristics?
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Does a diode show an "effective resistance" in a circuit, and how does that affect current drawn?
I was taking some measurements on a simple circuit consisting of a 3.7 volt battery (an old one used for vaping and such), a 20mA LED that has a listed voltage of around 2.3 V, and a resistor of about ...
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Determining ideality factor of diodes from IV curves
I'm currently doing a semiconductors lab and one of the tasks is to examine the IV characteristics of diodes to determine the values of the ideality factor, $n_{id}$, and the reverse bias saturation ...
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What does the $R$ in the formula $P=V^2/R$ for power represent?
We know the following formula:
$$P=V^2/R.$$
I want to ask what the $R$ in the above formula represents. Is it the normal resistance of the resistor (load) or is it the increased resistance of the ...
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1
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What does a Space radiator/cooler look like exactly? [closed]
I understand the principles of radiating heat to space using heat pipes and whatnot but what exactly do these devices look like in real world applications? The closest example for a space base ...
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1
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Getting Energy consumed by using the Gradient of the Power
My goal is to predict the energy consumption in Wh over a time window by using the current power draw and the current gradient of this power draw. In other words, if my power usage is increasing at ...
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How do I find value of $I$ using Node Voltage analysis method? [closed]
How do I find value of current $I$, using Node Voltage analysis method ?
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How to derive Thevenin Voltage formula using Kirchoff laws?
Here's a simple voltage divider. I'm learning Thevenin Circuits now and we use the formula for Thevenin Voltage a lot (very useful!) but I'm not sure how the formula arises. My professor said I can ...
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