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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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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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44 views

Why does current not increase when the voltage increases in this case? [migrated]

When talking about BJT transistors, a very common graph is the one shown below, that plots (VCE,IC) as an ascending function. As far as I know, the BJT manages VCE so that IC is beta times IB, being ...
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3answers
76 views

Summing up very basic terms in basic electricity [closed]

My attempt to define following terms as per my understanding. I am currently at high school. Electromotive force (EMF): Potential between two terminals when open circuited. Wikipedia's ...
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0answers
42 views

Why can’t we use the other formula for heat in this?

Two conducting wires of the same material and of equal lengths and equal diameter are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat ...
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27 views

How does a power amplifier works? Does it change the shape of the output signal? [migrated]

I was doing some experiments and I had to put in input a 2V sinusoidal signal at 20Hz through a power amplifier and I got in output an overloaded square signal at +15/-15V at 20Hz. Is it normal? I ...
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1answer
61 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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0answers
21 views

Magnetic moment of copper

I am told that copper is diamagnetic and all diamagnetic materials have a magnetic moment of 0 or less than 0 due to their fully paired electron. Now the main question is copper being diamagnetic ...
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0answers
18 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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3answers
53 views

Question about full wave bridge rectifier

Sorry if this is a stupid question, what I know is when a diode is forward biased, it conducts current, when it is reverse biased, it acts as an open branch if its $ PIV \geq V_{in}$ But in this ...
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19 views

Why does nMOS using N+ gate have lower Vth than nMOS using P+ gate ? (w/o band diagram)

I understand it from band diagram.(Band bending is more stiff in N+ gate case) However, I don't know what's essentially happening. If P+ gate and N+ gate have same dose, their poly depetion will be ...
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2answers
65 views

Difference between diode and LED

What is the difference between a diode and a led? I know a led is a diode and I know how they are used and so on but I'm not really sure why a regular is not also light emitting. Therefore, what is ...
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1answer
18 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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1answer
67 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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0answers
24 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
33 views

How do you calculate the capacitance of a parallel plate capacitor with multiple dielectrics? [closed]

My question is how would you go about calculating the capacitance of a parallel plate capacitor which has two mediums in between the parallel plates. I am aware that for a regular parallel plate ...
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1answer
25 views

In which region of diode breakdown starts?

i confused about in which region of a diode breakdown start, in some books it is given that breakdown starts in depletion region but in some other is said that it start in p-side or n-side of diode (...
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1answer
26 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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0answers
27 views

Splitting of energy levels in solids [duplicate]

when atoms are well seperated energy spectrum is discrete, but when they come together energy levels split and they form bands, upto this i can understand. where im confused is that these splitting ...
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2answers
31 views

Voltmeter connection across motor

I want to measure the voltage(potential difference) acorss the motor A. Where should I connect the voltmeter? I am confused between two possibilities: between X and Y (between two ends of the motor ...
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3answers
57 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
23 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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2answers
86 views

Common potential of two capacitors

I read in my textbook that when two isolated capacitors are connected to each other, redistribution of charge takes place in such a way that they both acquire a common potential. My question is why ...
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1answer
35 views

Why can I hear the treble sounds through a speaker, such as on my phone, better than I can with headphones?

I'm not sure if this is related to my hearing loss, or if anyone else has noticed it, but I find it easier to hear higher frequency sounds coming out of a speaker that I hold up against my ear versus ...
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3answers
158 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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1answer
29 views

How does a sound box amplifier work?

I read in a few places that in a guitar for example, the vibrations are passed through the connectors to the wood and the wood with its bigger surface is more efficient as a coupler to the air, ...
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2answers
45 views

Principle of potentiometer

I could not understand why the emf of the main cell (labelled E) in the circuit (can be a battery eliminator) should be greater than the emf of the cells (E1 and E2) used in the secondary circuit. ...
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0answers
16 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?
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2answers
54 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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3answers
208 views

Is there a physical limit to memory reading and writing speed?

Is there a limit to the speed at which a memory, quantum or classical, can be read or written into? I've seen this interesting question : Is there a physical limit to data transfer rate?. Here I'm ...
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1answer
27 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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0answers
12 views

Why is the maximum voltage applied to the coil different when disconnected from the battery?

In this RL circuit, the time to reach the point V=0 (after the switch was turned to (a)) was about the same as the time after switched to (b). But my teacher says, (in the experiment) peak voltage ...
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1answer
22 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
34 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
37 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
43 views

Need of LED Modulation

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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0answers
50 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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0answers
50 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
68 views
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1answer
80 views

Accelerometer readings

Good Night. I have a implemented a 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 ...
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1answer
47 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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2answers
766 views

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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1answer
65 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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1answer
29 views

What does ground in low voltage electronic circuits mean?

I have been confused a lot by the word "Ground". The ground that I've usually heard about is connecting a wire of appliances with the rod buried under earth but what does the word Ground mean when it ...
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2answers
64 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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0answers
34 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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1answer
48 views

Bjt configuration

In common base configuration,we know that alpha is almost 1 which means that the base current is almost zero.But what is the physics behind this base current almost equal to 0?And similarly in common ...
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1answer
50 views

Ohm's Law in Practise [closed]

When the AUX pin of a stereo is connected to my mobile phone's audio female port, I just measured the voltage at the end of this AUX pin (No load is connected) approximately 2mV using a DMM. But when ...
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2answers
788 views

Why does sticking a knife into an operating toaster give you a shock?

I understand why sticking a knife into a toaster produces an explosive phenomenon. It completes the conductive connection between the two holes in the electrical outlet and the 250 volts or so that ...
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1answer
156 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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2answers
84 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 ...