# 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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121 views

### Equivalent DC circuit with charged conductors

I am trying to find equivalent circuit for a circuit composed of interconnected capacitors when isolated pieces of conductor may carry nonzero electric charge, and I have been struggling with this ...
1k views

### Half wave rectifier at high frequency and small amplitude ac signal

This is the picture taken from my oscilloscope where I was just checking how a standard half wave rectifier properties. The yellow one is input signal of frequency 20.5KHz and peak to peak value is ...
840 views

### Calculation of RMS current in half wave rectifier

While calculating RMS current in half wave rectifier, why we will consider only half wave that means only we consider the limits 0 to pi. But here RMS current is for AC input..so why don't we consider ...
2k views

### Voltage - Energy drop

I'm having a hard time understanding the nature of voltage and am hoping you guys can help. The main issue is the concept of the voltage drop. Take the following circuits : In regard to the first, ...
140 views

### About the combination of two signals with capacitors

Here is a link of an article I've been reading. http://www.analoguehaven.com/moog/thereminblack/hotrod.pdf In page 4 there is a circuit schematic. Notice there is a part called variable pitch ...
829 views

### electron-gas theory of a metal (drude model) - intuition

I'm back to studying "Microelectronics" by Millman & Grabel (2nd ed.). The book makes some references to the electron-gas theory, and I found out to have some problems with my intuition. At each ...
989 views

### Question on Shockley's equation for FETs

I'm currently studying FETs (Field Effect Transistors) in Navy school. What I know so far is that in FETs, $V_{gs}$ is reversed biased, creating a depletion zone. What this means in plain English is ...
234 views

### Is a motor HP torque directly proportional to the increasing HP among identical motors?

Say you have three motors: Motor 1 = .10 HP with x torque, performing task A Motor 2 = 1 HP with y torque, performing task A Motor 3 = 10 HP with z torque, performing task A If the motors are the ...
39 views

### Generator phase noise influence on its averaged signal

I need to estimate averaged signal of a generator with known phase noise and the amplitude noise can be neglected. The averaged signal of the generator is expressed as:  \langle A\exp{i(\Omega t + \...
288 views

### Spin FET Transistor

Spin FET Transistor. When a gate voltage is applied to a current of spin polarized electrons, a spin precession will occur. If this spin precession is enough to make the bulk electron spin ...
504 views

### What is the speed of electrons in a transistor?

What is the average speed of an electron in a MOSFET transistor, and how can you calculate this? I've heard people throw terms such as "drift velocity" and "Fermi velocity" around, but I've never ...
862 views

### Can you replace the backlight of a thin film transistor (TFT) with a mirror?

I basically know how TFT' displays work. They have on both sides a polarizing foil, in 90 degrees with the crystals in the middle modifying which light particles should pass through or not. The light ...
825 views

### Electronic filter

Can you explain, please, step-by-step how an electronic filter does work? For example, high pass filter. I know It's a trivial things, but I can't get it completely. Don't bring me formula and etc. ...
5k views

### PN Junction Depletion Region

So it took me a little bit to understand this, but I want to make sure I have a few things right. First of all, when a Crystal Structure with One side N-Doped, One Side P-Doped are in the same ...
22 views

### What are good books and other resources to study the Cryogenics?

I'm beginner in cryogenics. Also please suggest something which will be useful for study of Electronics at Cryogenic Temperatures.
9 views

### Confusion regarding the quasi neutrality approximation for PN Junction analysis

Why are they called quasi neutral and not exactly neutral? What happens which make them that? In the analysis we have done to derive the I-V characteristics , we always maintained neutrality where ...
12 views

### How do you calculate the reflectivity of material from its conductivity?

How do you calculate the reflectivity of material from its conductivity? For example, gold at v=9x10^12/s (this problem is from the electronic property of material by Hummel). Is it possible to use '...
22 views

### Is “quaternary” adjective redundant while speaking of InGaAsP?

I'm reading an article. One sentence looks as following: The 500 nm thick waveguide layer consists of an InGaAsP quaternary layer But since InGaAsP is quaternary compound, why do they write ...
22 views

### Signal demodulation in a frequency mixer

Let's assume we have a signal $f(t)=A\sin(\omega t)+B\cos{\omega t}$. In order to isolate the '$A$-part', the signal is mixed with an oscillator signal $g(t)=\sin(\omega t)$ generating a constant ...
27 views

### Why does increasing capacitor dielectric allow it to store more charge under constant voltage?

Take two capacitors that are each connected to and charged from identical constant voltage sources. The capacitors are identical in every way (distance, area, etc) except that their dielectric ...
40 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 ...
24 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 ...
17 views

### Why doesnā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-...
43 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....
102 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 ...
39 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 ...
54 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 ...
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 ...
17 views

### How to produce Sratic RAM using 10nM technology [closed]

If I want to produce 2GB SRAM module using 10nM or smaller than 10nM technology, what should I do? Please state step by step and also how much would it be?
219 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 ...
60 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 ...
464 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 ...
281 views

### What is the resultant resistance of the circuit [closed]

If all resistants have a resistance of $R$, find the resultant resistance between points $AE$. My Try: Since Points AB and AC have equal resistance, There's an equal current flowing through each ...
576 views

### Why is voltage gain highest in common base transistors whereas lowest in common collector transistors? [closed]

Although the common base transistors have current gain lowest and the common collector transistors have current gain highest.
59 views

### Why do the following Network Transformations give different answers?

I did a Star to Delta Network Transformation and a Delta to Star Network Transformation on different parts of the original circuit as shown in the image below. It gave me two new circuits. On solving ...
48 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 ...
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 ...
72 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 ...
43 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 ...
59 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 ...
156 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 ...
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 ...
167 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 ...
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 ...
1k 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 ...
121 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?
197 views

### Normalizing temperature data of CPU sensors to ambient [closed]

My scenario: I want my application to stop or take some decision based on temperature. say like if my ambient is morethan 41 i want to switch off the application and we do not have an separate ...
113 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,...
68 views

### Cds photoresistor cells [closed]

We understand (from Wiki) that when light hits the photoresistor cell, the resistance goes down, electricity flows more easily. But dont understand how resistance going down would work to turn OFF a ...