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.
556
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P-I-V laser diode characterization: Integrated sphere or not?
I read that to do a P-I-V laser diode characterization there are two ways:
-Coupling the laser to the Detector through an Integrating Sphere.
Setup would be: laser diode-integrated sphere-...
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3answers
59 views
Understanding simple LC circuits
I'm trying understand the physics of simple inductor-capacitor circuits such that there is just an inductor L and a cacpacitor C and a switch.
Imagine first that the capacitor is fully charged and ...
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73 views
Conceptually understanding RL circuits
I'm struggling to conceptually understand the current-time profile of an RL circuit. Specifically, what causes the rate of change of current, $\frac{\partial i}{\partial t}$, to start off high when ...
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24 views
What does mean an electronic symbol of operational amplifier, but with only one input?
What does mean a symbol of operational amplifier with only one input ?
See for example :
http://physicsopenlab.org/wp-content/uploads/2016/11/CSP.png
Does this means that the + input of the ...
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22 views
No commutator or rectifier?
Homopolar motors and generators don't need a commutator or rectifier. Are there any other motors or generators that don't need a commutator or rectifier? If so, what are they?
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172 views
Hydraulic analogy for electrical compounds
I want a source (website or a book) where there are hydraulic simulation (or analogy) for all (or at least the most useful) electronic compounds?
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35 views
The physics of microwave vacuum tubes
I've searched this extensively, but I couldn't find anything (the only thing I found was this one). I know this question seems to be more of engineering than physics, but I've found some engineering ...
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3answers
40 views
can there be a circuit that changes its input source after a certain limit of voltage is hit? [closed]
I have only recently started learning about circuit components and only know about common components such as a capacitor and a little about diodes, so excuse if im not able to understand common terms ...
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25 views
How to synchronize a pulse from function generator and an external pulse
I am currently trying to sync two pulses. One is from a function generator(5V, 1MHz) and the other is from femtosecond laser(which is 76MHz). The femtosecond laser has a {38MHz, 2V} pulse thats in ...
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74 views
Electron gun design
I have a question about electron guns. I have read a lot, and all designs use high NEGATIVE voltage ($-1000$ V for example). Is possible to use high POSITIVE voltage like this drawing? Or do you think ...
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41 views
Electronics and junctions
In a p-n junction, is it only the electrons that move from the n-type part to the p-type part in order to create a depletion region or is it the movement of both electrons and holes from the n-type ...
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51 views
How to choose the method of circuit analysis?
I was just doing some revision, and I was wondering how to figure out which method to use for solving a given circuit? I tried using mesh analysis on the attached circuit but I got it completely wrong....
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89 views
Derive the formula for a capacitive voltage divider?
I've seen the derivation for a resistive voltage divider, Vout = Vin * R2/ (R1 + R2). For a capacitive divider, Vout is reported as Vout = Vin * C1/ (C1 + C2) - for example see https://en.wikipedia....
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434 views
Are holes electrons moving in the same direction of the electric field?
Holes are electrons, but with negative mass. That's said, so by applying electric field, electrons(n) move in the opposite direction of the field, while holes(other electrons) move in the same ...
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58 views
Will stacking 2 peltier coolers on top of each other reach a lower temperature quicker?
I'm working on a project where I'm trying to get freezing (<0 degrees Celsius) temperature as quickly as possible. Clearly, stacking 2 peltier coolers on top of each other will be less efficient ...
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1answer
35 views
What does the phase discriminator portion of the Costas Receiver do mathematically?
What does the phase discriminator portion of the Costas Receiver do mathematically?
The output of the $I$-channel is $ \frac{1}{2}A_C \cos \phi \, m(t) $. Which means for small deviation of phase $ \...
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331 views
How do I connect a four way key in a potentiometer?
How do I connect (which wire to which terminal) a four way key to a Potentiometer to compare the EMF of two cells.
Circuit diagram and a four wayway key is shown in the pictures.
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69 views
NPN transistors reverse biased
How is a pn reverse bias junction is formed in a NPN transistor? In a normal pn diode during a reverse bias junction an 'internal battery ' is formed which counteracts the movement of electrons . But ...
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1answer
41 views
Acoustics - tiny ultralow impedance speaker? [closed]
Here's a theoretical question that hopefully someone will be able to shed some light on. Apologies if this is the wrong forum, I figured the electrical engineering community would be more into ...
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3answers
95 views
Why would Low Voltage produce HIGH current with the same resistance? Transformers
We always see in Ohm's law that $v=IR $. So if $R$ is fixed for a wire, how can the electrons with High P.D have low current. Isn't it the electrons bumping into the resistor that creates the heat? ...
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1answer
31 views
Uncertainty estimation of a quantity after its calibration
I have to calibrate power output of a diode to its input voltage. The voltage source has negligible error but the power meter has significant uncertainty (a couple %). I take a number of power ...
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1answer
41 views
Defining potential of the ground
In electronics, it is customary to define the potential of ground (thinking the Earth as a large conductor) as zero. Is this consistent with the fact that the Earth has a net electric charge that is ...
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1answer
37 views
Error of capacitnace measurement using a multimeter
physics stack exchange
Many multimeters have a setting for measuring capacitance. The multimeter I have has a precision of four significant figures, or in other words, it returns the value in the ...
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1answer
88 views
How do multi-meters measure capacitance?
Many multimeters have the ability to measure capacitance along with the ability to measure AC voltage, DC voltage, current, resistance ... The only equations I am aware of that determine capacitance ...
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2answers
186 views
Why diodes can be used to create a current-independent voltage drop? [duplicate]
How is current independent of the voltage drop in a diode?
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1answer
428 views
How to determine linear acceleration using an accelerometer?
I have a implemented an accelerometer, a gyro and a Magnetometer in Raspberry Pi.
I want measure the linear acceleration (acceleration without gravity) but I don't know how to do it or if it is ...
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42 views
How to decide the resistance required to power a LED using triboelectric nano-generators?
I tried to power LEDs using triboelectric nanogenerators, https://youtu.be/OAmpvhRE4Ws, but found that I was unable to light even a single LED. Do it requires to connect resistors in series with LEDs ...
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1answer
48 views
Voltage across different power sources and transformers [closed]
Something cause a potential difference between the two poles of a power source. The same kind of 'something' of two different power sources may also cause a voltage between those two different power ...
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1answer
39 views
Limit charge of electronicāhydraulic analogy of a compartment
I am doing a mathematical model of an hydraulic system and I am using an electronic-hydraulic analogy. Normally a compartment is simulated with a capacitor.
But in my system I can apply a big ...
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1answer
652 views
How does base-emitter voltage affect the current gain of a transistor?
I'm doing a Physics project related to transistor operation. My data shows that as the base-emitter voltage drop increases, the current gain of the transistor rises and eventually plateaus at a ...
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1answer
340 views
Internal resistance and a resistor as a potential divider
Based on the fact that batteries have some kind of internal resistance, if I had a circuit that consisted of a battery and a resistor of some kind would they act like a potential (voltage) divider?
...
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32 views
Band theory- Is the conducting band the last orbital with a gap between the two bands?
What I understand is in each atom there are conducting and valence bands
and the valence band, the minimum level for electrons (is the orbital before the last)
Is the conducting band the last ...
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1answer
356 views
Insertion of current carrying metal sheet between the plates of parallel plate capacitor
A parallel plate capacitor with area of plates A and distance between them d is charged with Voltage V1. A metal sheet carrying current is inserted between the sheets. How does the system change? What'...
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60 views
Using DC voltage in Transformers
I understand that a transformer can step up or step down voltages when it is fed in AC. However, I am wondering why can't we use a non constant DC source as input.
For example, if I rectify the AC ...
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1answer
117 views
Nuclear physics timing experiment without Amplifier
I am quite new in nuclear physics instrumentation. So my question may seem silly.
We are performing timing experiment in our lab to obtain better time resolution of NaI(Tl) detectors in conjunction ...
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1answer
102 views
Saturated BJT Transistors. V CE < V BE : AKA - Things that make you go āHmmmmā
At the risk of being blasted for cross-posting, I am posting this question again here in the Physics department. It is a duplicate of this post in the EE forum. However, I would like to get some ...
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70 views
Saturated BJT Transistors. $V_{CE} < V_{BE}$ : AKA - Things that make you go “Hmmmm” [duplicate]
We use them every day and those in the know fully understand the functional characteristics of BJT transistors. There are documents and links galore explaining the operational math. There are even ...
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29 views
In mechanical systems, it is easier to understand concept of natural frequency, could somebody explain natural frequency in electronic elements?
In mechanical systems, natural frequency simply means the frequency at which the body will oscillate when it is disturbed(assuming the body will suffer zero resistance in motion) but wihle studying ...
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1answer
25 views
How to convert a noise spectrum to noise per root Hz
I have measured the phase variation of laser and did the FFT to get the spectrum. How can I convert my data to the conventional noise per root Hz form?
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1answer
24 views
What are the detectors used to count electrons in modern day spectroscopic tools?
I was taking a course in electronics. Scintillation counters, Dynodes, Channeltrons are some of the common names in counting elementary particles. When I entered an XPS lab, I saw "Detector used: PSD ...
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1answer
30 views
Is it feasible to model electronic components on “electron level”? Has it been done?
Is it feasible to model electronic components on "electron level"? Has it been done?
Reason to ask is that I've noticed that many practical models of electronics merely try to devise a function that ...
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2answers
203 views
Output in a half wave rectifier
In a half wave rectifier only a single diode is present. One end of the secondary wire of the transformer is connected to the p side of diode while the other to the load resistor. The n side is ...
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1answer
258 views
Patch antenna excitation
How can we excite the patch antenna in different modes like TM10 and TM30? If a microstrip patch antenna resonates at TM10 mode can it resonate in other modes also like TM30?
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104 views
What's a reasonable difference in resistance between batteries in parallel?
I know that the differences in resistance between batteries in a circuit will create different drop, and as a result draw unequally. Unfortunately, I couldn't get my hands on a parallel D-cell ...
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1answer
36 views
Current $i(t)$ in a “charged” inductor
I have this circuit:
with $$v(t)=-30e^{-5t}$$
and inductor 1 has a initial current of 3A and inductor 2 of -5A.
My roommate and I are disagreeing about the current i(t).
Since it is $$i(t)=1/L \int ...
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169 views
Breakdown voltage avalanche photodiodes
What is the best definition to obtain the breakdown voltage of an avalanche photodiode?
Update: Is it even possible to determine it graphically? E.g. by fitting a linear function or 1/x or something ...
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1answer
41 views
Is the simplification of this circuit correct?
It doesn't look right to me as the 8 and 4 resistor and the 30 and 17 ohms resistors just disappeared. Can anyone point out the correct way of simplifying the circuit and providing the equivalent ...
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44 views
How to estimate an influence of electromagnetic devices on each other?
I have a few electomagnetic devices: one is a gps antenna, next is a receiver (950 Mhz), third is a radio transmitter that radiates with 2.41 GHz and the last is a height sensor that uses 24 Ghz ...
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1answer
481 views
About The foxhole radio: coil rotation times, whether capacitor's needed
I recently tried to make a DIY foxhole radio. Althogh I made it according to the manual (140times coil rotated, ground(220V), blued razor blade, pencil core and antenna (just a steel stick about 1 ...
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466 views
Why do vinyl gloves work on my touch screen, while other objects don't?
If I use a rubber or plastic object on the screen of my smartphone (Galaxy S5), the digitizer does not register the contact.
According to my understanding, the reason it registers fingers but not ...
asked Aug 13 '17 at 9:25
Revetahw says Reinstate Monica
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