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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Smallest minimum feature size possible for transistors printed by photolithography

I'm doing a project about Moore's Law, one of the subtopics I've come to is photolithography. The way I understand it is that the MOSFET transistors are currently printed on a silicon wafer by ...
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1answer
57 views

Different Color Intenensities from simple ON/OFF RGB subpixels

I recently got interested in electronic paper. One design that I liked was the one from Mirasol: https://en.wikipedia.org/wiki/Interferometric_modulator_display However, what I don't understand, is ...
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123 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 ...
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89 views

Can you get a better signal to noise ratio by connecting multiple microphones in series?

From my very basic understanding of microphones, they generate a tiny bit of electricity as the membrane moves, this is the signal. It would stand to reason then, that if I connect a bunch of ...
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49 views

Distance $E_F-E_i$ in a compensated semiconductor

Given two energy level diagrams for a compensated conductor: At $0~\text{K}$ At $500~\text{K}$ I want to determine for which diagram is the Fermi level closest/farthest from $E_i$. It's a ...
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31 views

What is phase sensitive detection?

The lock-in amplifier is said to have a phase sensitive detector which compares the phases of the reference and incoming signal and is thus able to recover a weak signal from an overwhelming ...
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104 views

Conductivity of a heavily doped semiconductor at Absolute zero temperature

As the Fermi level moves toward the conduction band in an n-type semiconductor; when heavily doped, it moves into the conduction band of the semi conductor. So, will the semi conductor behave as a ...
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97 views

Can seebeck chips be used to extract Peltier chip waste heat?

I understand that a problem with employing the Peltier effect for the purpose of cooling is that it produces a significant amount of heat on the hot plate. But why don't we use seebeck optimised chips ...
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29 views

Have the BaF2 scintillators a strong correlation with the input current that cause the shifting of the centroids in the distribution?

In gamma gamma correlation I suspect the presence of systematic error maybe caused by a non optimal voltage according to someone there is a quadratic correlation between centroids position in the ...
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399 views

Piezoelectric effects of naturally shaped quartz crystal for maximium Q?

Background Based on helpful comments and links here and also from my question on the electronics stackexchange, I have learned that the quartz crystals are nature's transducers of energy, allowing ...
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641 views

Concepts in Gabriel Kron's later papers

Gabriel Kron was an important research electrical engineer known for applying differential geometry and algebraic topology to the study of electrical system. Towards the end of his career he published ...
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2answers
105 views

$1/f$ noise: is it limited?

Basically my question is: I have this doubt because in contrast to the limit $f \to \infty$ (which is an idealization because all system behaves as a low pass for enough $f$), we can perfectly build ...
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36 views

How does a transistor work in an electric circuit?

For example, if this is the circuit containing the transistor: The positive holes move to the right hand plate of the collector. The electrons must be moving in the opposite direction from the wire ...
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23 views

Solar cell: Surprising change in EL for varying PEDOT:PSS-thicknesses

I am currently working on improving a solar cell, which is partly transparent and therefore utilizes two transparent electrodes (TCO on top and PEDOT:PSS on the bottom). As PEDOT:PSS alone is not ...
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14 views

Why doesn’t the focussing anode diverge the electron beam again?

Consider this diagram of a focusing anode in a CRT: Question: Why does the electron beam not diverge again when it enters the focussing anode (or accelerating anode) while leaving the pre-...
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39 views

Lagrangian Mechanics to solve arbitrary maximization problem

I've been thinking for some time about how to better find the optimal weights for neural networks and it struck me that when solving Lagrangian mechanics problem you are optimizing the action function....
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63 views

Photo Multiplier Tube (PMT) and charge sensitive pre-amplifier

I have an H7195 assembly type Photo Multiplier Tube (PMT) used to be tested for single photon measurement. I would like to use the dynode output to check the spectrum by connecting to a charge ...
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38 views

Analysis of a simple system consisting of a transformer

Considering a transformer whose second winding is connected to a resistor, such that alternating electric current is induced in the secondary winding by the primary, an attempt of analyzing the ...
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2answers
49 views

Electromagnet produces sound from hollow pipe

I have wrapped around a 80cm metal pipe some copper wire and attempted to produce an electromagnet. The electromagnet works nonetheless from the extremities of the metal pipe a sound is being produced ...
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30 views

Can anyone help me to clear some questions about diodes and transistors?

i don't understand the basic of the working of diodes, because i imagine that if we have a n-p junction and we want to pass current through from side of n region to p region, if we beat the potencial ...
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138 views

Why the product of hole and free electron density is constant in semiconductor?

I have learned from a text book of electronics that the free electron density, n (which is equal to that of hole, p) of intrinsic semiconductor due to thermal excitation is a function of temperature ...
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58 views

Calculating length of stretched wire (before and after) based on resistance

For a university project; I'm interested if I can accurately calculate the lengths of a wire (or any electrical conductor) before and after stretching. I understand that there are multiple factors ...
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2answers
87 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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1answer
378 views

How can depletion region be formed at the center?

Let's consider an electron at the junction in the n-type region. As it moves into the p-type we say it leaves behind a positive ion and hence in this way electrons at the junction in the n-type create ...
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1answer
445 views

Why is voltage gain highest in common base transistors whereas lowest in common collector transistors?

Although the common base transistors have current gain lowest and the common collector transistors have current gain highest.
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1answer
46 views

Help with $I$-$V$ Characteristic of a Diode

I am struggling to understand why I can't get a full voltage range when I have the diode the correct way round. If you check this link: https://electronics.stackexchange.com/q/266201/ If you look at ...
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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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2answers
437 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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71 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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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 ...
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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 ...
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1answer
111 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 ...
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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 ...
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158 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 ...
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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 ...
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932 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 ...
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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?
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105 views

what is the effect of temperature on the resistance of a photoconductor?

As we know, for a photo conductor resistance tends to decrease with increase in irradiance, but with greater irradiance comes greater temperature. Also we know, photo conductors are semiconductors,...
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110 views

Electron jump into a transistor to read qubit state

Prof. Andrea Morello, a quantum physicist, in one of its quantum computer models uses the spin of the outermost electron in a phosphorus atom to represent a qubit. This atom is embedded to a transitor....
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39 views

Electron gun and oscilloscope

Aren't the electrons exhausted in the electron source of electron gun? And what is the fate of electrons that strike the sulphide coated screen to produce luminescence?
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56 views

Why does the metal mesh in an electric swatter make a whirring sound?

I have an electric bug swatter that operates on a rechargeable lead acid battery. I had one before that operated on disposable batteries and when it was turned on, it made a high pitched whining noise....
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2k views

Exact (quantitative) definition of “knee” and/or “cut-in” voltage?

Sort of a 2-part question: 1) I know they are used interchangeably but are the "knee" and "cut-in" voltages of a diode actually the exact same thing? I had thought that the "cut-in" voltage was ...
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58 views

How to produce sine wave heat generator?

I have taken a lab course this semester and in the experiment of finding thermal diffusivity of brass they are using square wave heat generator(by a simple circuit which gets on and off at regular ...
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330 views

Numerical Solution of 1D Boltzmann Transport Equation

I need to solve the one-dimensional Boltzmann transport equation in a semiconductor numerically, and I want to take a deterministic approach toward the problem (i.e. not use Monte-Carlo or similar non-...
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691 views

How is the bandgap reference diode so accurate? (temperature changes bandgap?)

I am studying about bandgap references (wiki). As a black box approach, (from what I know) it can be seen as a system which gives a stable voltage reference irrespective of the highly varying ...
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2k views

Graded semiconductors - hole concentration function of x

I'm stuck at page 37 of the (second ed.) of "Microelectronics" by Millman & Grabel, section "1-7 Graded Semiconductors". Before that section, it spent some time explaining the phenomenon of ...
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58 views

Discrepancy in introducing Schottky barrier

I have a problem regarding introduction of Schottky barrier in metal-semiconductor junction. Because of this barrier the energies of conduction band vary discontinuously and hence the potential is ...
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97 views

The things to consider when choosing a mesh for an electron detector (MCP detector)

I am designing a electron velocity map imaging setup. I need a copper mesh just infront of the detector to accelerate the electrons towards the MCP detector. I am doing the instrument design for the ...
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174 views

Is there an equation for the magnetic field of a conductor attached to a magnet?

Let's say I have a hollow conductive rod, 10mm diameter (O.D.), and I place a magnet of known strength 50mm up the shaft. What is the microTesla (mT) or Gauss (G) of the magnetic field (or flux ...
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898 views

Algorithmic approach for applying Kirchhoff's Rules to circuit analysis

Working with Kirchhoff's rules, I am attempting to device an algorithmic approach to finding the unknowns of the problems, I am of a Computer Science background and I am finding it difficult to ...