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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64 views

Understanding the principle of photo diode signal generation

I have two lasers, both illuminate on a photo diode, i'm not very sure what's physically going on in the photo diode. My understanding is the following: The electric fields of both lasers add up and ...
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24 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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23 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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159 views

Can four probe method be used to find resistivity of metals?

Can we use four probe method to find resistivity of metal/conductor. I searched the question on google, but could not find the answer. My guess is that we can use. Why not?
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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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0answers
18 views

Energy cost of calculation in non-quasistatic limit

The Landauer principle puts a limit to the cost of irreversible computations, namely that an operation that erases 1bit of information has a minimal energy cost of $E=k_B T \ln 2$. This limit is ...
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389 views

Minority charge carrier concentration in pn-junction during forward bias

my question: During forward biased, is it true that the minority concentration (e.g. hole in n-type) could be higher than the majority concentration of the same type (e.g. hole in p-type, which is ...
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2answers
2k views

How is it I can see the infrared Face ID on my iPhone X? [closed]

I’ve tried using Face ID in the dark on my new iPhone X and I can very clearly see the infrared flood Illuminator light up as well as the infrared dot projector. Is it possible for humans to see ...
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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 ...
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231 views

Why did Shockley's Copper Oxide Field Effect Transistor fail and has anybody succeed in creating a Copper as appose to Silicon based FET?

Reading Tomas Lee's very interesting historic account of Semiconductor's used in the Electronic industry: https://web.stanford.edu/class/archive/ee/ee214/ee214.1032/Handouts/HO2.pdf I wondered, why ...
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25 views

Irradiation influences on electronics/photodiodes

I'm working on the irradiation of a pool of 1,000 avalanche photodiodes. To make them radiation hard we irradiated them with 30 Gray before we mount them into a detector. The distance from the cobalt ...
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1answer
55 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 ...
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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? ...
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167 views

LC Circuit with a DC input

In the previous LC circuit, if we connect one end with a DC input voltage and the other with ground, what does the oscillating output wave look like? I know that if the capacitor was initially ...
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1answer
46 views

Relating to IR rays [duplicate]

I am working on a project where I am putting an IR sensor similar to what we use IR module for Arduino.I just want a material that can pass the IR rays but it should be opaque to visible eyes .Like ...
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2answers
68 views

Bike light: what consumes more current, continuously on or blinking?

I've been riding my bike many nights wondering the following question: What consumes my LED bike-light battery: the continuously on setup or the blinking setup? It might seem trivial, since the ...
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1answer
717 views

How do I calculate the low frequency and high frequency gains of an op amp amplifier?

Knowing the general process would be best, but this particular configuration is the one I need an answer for. for this problem low frequency is defined as $f \ll 159$ Hz and high frequency gain is ...
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2answers
157 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 =...
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2answers
278 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 ...
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1answer
98 views

Resonant frequency in RLC circuit

I know that in an RLC circuit the resonant frequency is the one that makes the total impedance purely resistive. So for this circuit: The impedance is $$ Z = R + \frac{\omega L}{1-\omega^2 LC}j $$, ...
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1answer
179 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
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 ...
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1answer
625 views

Why can't I use a gyroscope/accelerometer only as a compass?

I am seeing this from the usual smartphone sensors. These sensors (Android here e.g.) take the magnetic field data as input. That is okay, but some phones do not have a magnetic field sensor (they ...
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1answer
150 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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68 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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3answers
2k views

Use of slip rings and its working in a AC generator

What is the use of slip rings in an AC generator and its working? What would happen if there was no slip rings?
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1answer
34 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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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 ...
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1answer
16 views

Can i take a high voltage system and a high amp system and merge them?

Lets say i have a battery with 50A but a low voltage output and a 30,000V but with only a few amps cause it was converted for to the Voltage could i somehow create a system where the Voltage from one ...
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3answers
2k views

What are crystals used for in radio?

What are crystals used for in radio? I think I sort of know the answer to this but I would like a more detailed explanation. To my current understanding, piezoelectric crystals are used to modulate ...
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1answer
33 views

Can the telephone signals be tapped by an intruder? [closed]

I have a doubt. There are lots of telecommunication signals moving across the world, at the same time. For example, take the case of mobile phone calls. Millions of speech signals are propagating ...
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0answers
161 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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40 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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1answer
505 views

Larsen effect and pitch of sound

Why Larsen effect produces always high pitched sounds, never low pitched?
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2answers
40 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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2answers
404 views

What are the wavelengths of the red, green, and blue lights used for making LED pixels?

LED screens in televisions and smartphones use pixels that use a combination of Red, Green, and Blue diodes that can produce any color when used in the correct proportion of intensity. My question is,...
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2answers
578 views

Does an electron physically flow? [duplicate]

In a DC current in a conductive wire, is it more accurate to think of one electron wiggling its way through a sea of electrons... or to think of one electron bumping into another, which bumps into ...
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2answers
65 views

What is the difference between electricals and electronic?

In the case of circuits, we generally mention two types of circuits one is the electric circuit and another one is the electronic circuit. What is the basic difference?
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1answer
313 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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0answers
156 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 ...
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1answer
1k views

Why do lower frequency need more cone excursion?

I am not 100% sure about this,but my current understand of loudspeaker is that moving coil woofer with certain fixed value surface area playing 1000 Hz frequency at 100 dB spl will be moving back and ...
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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 ...
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0answers
69 views

Pulse shaping time related to number of counts?

I have a PMT (with a proton recoil neutron detector) hooked up to an amplifier, and when I increase the pulse shaping time from 0.5 microseconds to 2 microseconds, the number of counts recorded by the ...
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3answers
2k views

Backwards proof for balanced Wheatstone bridge

We know that in this Wheatstone bridge if, $\bf{I_3 = 0}$, it can be derived that $\bf{\frac{R_1}{R_5}=\frac{R_2}{R_4}}$ . But could we prove it backwards, mathematicaly, that - if in such a circuit $...
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1answer
273 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 ...
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2answers
1k views

Can higher order (more than 2nd order) differential equation be formed with electrical network?

Is it possible to have more than 2nd order D.E. in electrical network? Because order of d.e = energy storage element (i.e. capacitor and inductor). Actually i have seen only 2nd order d.e. so, can ...
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2answers
108 views

The importance of -20dB in signal analysis

I built a resonator designed to resonate in the 10MHz-1GHz range. To verify the resonant frequency I use a network analyzer with capacitor in series with the cavity to approximate the expected load. ...
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1answer
758 views

Diode-Resistor-Capacitor Circuit Equations

So I took the time to measure the current dependency on voltage of a diode I have. I applied an exponential fit to it, and have a pretty reliable equation (within 1%). I'm interested in how a diode-...
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1answer
42 views

How Can I Observe the Refraction of Infrared Waves?

It is my plant to propagate infrared and place a certain barrier in front of it. How would I go about observing the behaviour of the waves after passing this barrier?
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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. ...