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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Confusion on AC in LIVE & NEUTRAL WIRE

So if an AC current means the elctrons are alternating or changing direction in a given time, how does this apply to live & neutral wire, don't they flow in one direction only? Please answer it as ...
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118 views

Existence of conduction electrons in pure Si at room temperature

Silicon has a bandgap of ~1.1 eV whereas the room temperature thermal energy is ~0.04 eV. But we still find electrons in the conduction band for a pure silicon wafer, away from any radiation. I ...
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635 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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373 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 ...
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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 ...
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4answers
1k views

Potential Difference Across Components in Parallel & Series Circuits

So I have two questions, but they're kind of linked so I'm putting them in one. 1) I have a simple circuit with a battery connected to three lamps in series. If I then add a second battery but ...
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129 views

Why is electricity so successful (how to explain the variety of transducers we have discovered)

From piezoelectric crystals, to loudspeakers, microphones, hydrophones, strain gauges; electricity possesses the amazing ability to transfer energy/information to and from so many different media. I ...
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1answer
803 views

How big was the first transistor?

The first working point-contact transistor made in 1947 by Bell Labs. I'm looking for specific dimensions, all I've been able to find is "Fits in the palm of your hand".
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2k views

Why is spectral sensivity of a photodiode expressed in A/W

Can someone explain me the meaning of the A/W unit of the photosensivity when reading a spectral response function of the wavelength characteristic of a photodiode?
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65 views

How is quantum physics translated into the world of electronics? [closed]

I remember watching a documentary about early works in quantum physics and how it was essential to the microelectronics revolution and the invention of the transistor. What part exactly helped? Is ...
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187 views

How does the centre tap of a **centre tap transformer** at zero volts?

As per my knowledge, the secodary coil will have one terminal at positive and another 0(zero) at one instant, and at another cycle, the other terminal becomes positive and the first one become 0(zero)....
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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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686 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 ...
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116 views

Semi conductors (holes and electrons)

The following relation is mentioned in my text book for semiconductors in thermal equilibrium. $$n_e ×n_h = n_i^2$$ $n_e$ stands for the number of electrons. $n_h$ stands for the number of holes. ...
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217 views

Time delays in live TV talk shows

Quite often I observed that whenever a caller participates in a live TV talk show, there is delay of time to respond a particular question asked by the compère of the program. This delay is due to the ...
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928 views

Electrical analogy for stress and strain

It feels like the relation between stress and strain (and other mechanical properties) is analogous to that of some electrical properties (voltage and current?). I'm comfortable with electrical ...
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689 views

Explanation of NMOS processes

Gate (poly-Si + $SiO_2$) and $p^{-}$ silicon operate as capacitors. But how are voltages and charges applied? In order for inversion to occur, there should be charges formed in poly-Si, right? How ...
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376 views

Could a variable capacitor divider replace a Variac?

Hmmm... You can definitely drop down the voltage, and ideal capacitors don't dissipate any power. So it seems, at first glance, that you could use a capacitor divider as a lossless voltage step-down ...
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103 views

How can I calculate the equivalent resistance of this circuit with resistors in parallel with wires? [closed]

Problem: Calculate the equivalent resistance, $R_\text{eq} ,$ of this circuit: $\hspace{50px}$. My solution attempt Тhe $12 \, \Omega$ resistor and the $6\, \Omega$ resistor are in parallel, ...
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3k views

Non-ohmic conductors

Non ohmic conductors are said to be the conductors that do not obey Ohm's Law. The V-I graph for them is not a straight line unlike ideal ohmic conductors. According to me Ohm's Law states: The ...
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74 views

Why can’t light induce a current while microwaves can? [duplicate]

Microwaves can induce current in a coil of wire why cant visible light do the same?
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78 views

Need of LED Modulation [closed]

I have an experiment of calculating the velocity of light by using phase difference produced (link of the experiment is at the end). The experiment has a control unit which has an LED installed to ...
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141 views

How could a bulb light up if aĺl the voltage is lost in the resistor?

I recently came up with this slight confusion about voltage loss in resistors/resistance. So for example My circuit has a 12V battery, a 2 Ohms resistor and a Bulb. If we use the V=I.R formula then a ...
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3k 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
614 views

Larsen effect and pitch of sound

Why Larsen effect produces always high pitched sounds, never low pitched?
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68 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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2k views

Can we “use” a capacitor while simultaneously charging it?

I know that capacitors can be charged to work like a battery . But I wanted to know whether we can charge a capacitor while it is in use ( given that the current supplied to it is more than what it ...
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3answers
797 views

Why is $np$ always equal to $n_i^2$?

For you guys who studied semiconductor physics must be familiar with the equation: $$np=n_i^2$$ I can understand why this is true for the intrinsic case (the broken bonds would always provide ...
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1answer
347 views

Do oscilloscope have a lifetime? [closed]

The electron gun in an oscilloscope is, from what I understand, analogous to the one of a Cathode Ray tube. It is made of a material that emits electrons via thermionic emission. Doesn't this slowly ...
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750 views

How does the tuner really work in a crystal set?

I would like to know how and why the tuner works in a crystal set radio. I already know all the theory and the "formal definitions" (this creates a resonant circuit which responds to an alternating ...
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101 views

Stroboscope's unit

Can someone please tell me why does stroboscope's unit is rps or rpm. Revolution per minute/second. Although the stroboscope used was an electronic stroboscope. Is it has something to do with the ...
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1answer
556 views

why some elements of same group cannot be used for doping semiconductors?

15th group elements like As, Sb, P can be used for doping whereas N and Bi cannot be used for doping even though they too belong belong to 15th group. Why ?
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160 views

Diodes (Forward biased)

Why does the width of the depletion region decrease,when the diode is forward biased?Is it because the ions have moved to p-junction,or n-junction? Please clarify.
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7k views

Electrical conductivity of an intrinsic semiconductor

On which factor does the electrical conductivity of an intrinsic semiconductor depend? It doesn't have an excess of charge carriers in fact, does it?
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446 views

Nodal Analysis of an electrical circuit

I have several doubts about solving circuits. Can any circuit be solved using Nodal Analysis? If some circuit can be solved using Nodal Analysis, can it be solved using Mesh Analysis too? Why do we ...
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2answers
1k views

Horsepower achieved with multiple motors

Scenario I'm planning to build an electric motor for fun (not for any practical purpose). I recently purchased a shapeoko CNC mill kit and intend to manufacture most of the parts housing, stator etc. ...
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1answer
87 views

Drift velocity component of electrons in alternating current

I'm not sure if this question will qualify as cross-posting, but feel free to tell me if it does so that I can delete it. However, this question certainly does relate to both physics and electronics, ...
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1answer
52 views

Resource recommendation for spintronics

What are some good beginner level books to understand spintronics. I am looking for some sources in which basic mathematics of spintronics is properly explained.
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1answer
54 views

mechanical analogy to signal propagation on coaxial cable

EDIT: The analogy is wrong if we think of voltage propagation, I confused and in the eletrical signal, it actually happens contrary to what the analogy predicts. However, for current, it holds. I am ...
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1answer
54 views

Imprecision in experiments

When dealing with breadboards, and electronic circuits in general, in my case finding the total (equivalent) resistance using an ohmmeter, what are the factors that make the experimental value not ...
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1answer
179 views

How to utilize the Rashba effect in spin field effect transistor?

The conventional nano-electronics are confronting many bottlenecks and spin-based devices have become the candidate for the next-generation nano-electronics (spintronics). A semiconducting channel ...
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201 views

Reason for a thin base of transistor

I have been recently asked the following question: Why is the base of a transistor kept thin? MY ASSUMPTION Base is kept thin so that not many charge carriers could be neutralized in the process ...
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1answer
288 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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75 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
681 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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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
278 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-...
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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?
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1answer
225 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 ...
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40 views

The microprocessor built up from several hundred to several thousand atoms [closed]

Is it possible to build a simple microprocessor with up to several hundred to several thousand atoms? The microprocessor (only integer operations) should implement the basic operations (+, -, *, / and ...

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