# Questions tagged [electrical-engineering]

The engineering discipline concerned with the study, design and application of equipment, devices and systems which use electricity, electronics, and electromagnetism.

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6 views

### OrCad Capture Lite [closed]

In which library can resistor be found in OrCad Capture Lite?
19 views

### If the rotational speed of a turbine at a power plant doubles, does its voltage, current or power double? [closed]

Somehow, I cannot find a simple answer to this question, or a simple equation or equations... All other things being equal, if a turbine at your local power plant instantaneously doubles its rpm (or, ...
• 3,735
8 views

### STM microscope kinematic movement [closed]

I found the project for STM microscope, where kinematic movement is regulated with three fine adjustment screws: STM scan head. I own a double frame with two fine adjustment screws on diagonal and the ...
124 views

### Kirchhoff's voltage law, signs?

Consider the circuit below from the book Electrical Engineering, Principles and Applications (p. 95). According to that book, we get from Kirchhoff's voltage law that $$-v_1+0.5v_x+v_2=0$$ However, ...
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13 views

### Construction of transistor using diode? [migrated]

Construction of transistor using diode? Can we use diode as an transistor, I have gotten a assignment to give a presentation on this, I’m unable to understand the question and would like help from the ...
27 views

### Hole concentration distribution in MOSCAP

For a given p-type MOSCAP energy band diagram, I was asked to sketch the distribution of holes with respect to position. I understand why the hole concentration at the interface is $10^{10}/cm^3$ and ...
81 views

### How does RGB really work with subpixels?

first off, I’d really appreciate any help. I have googled relentlessly to try to understand this, but I’m too stupid to fathom it. Please attempt to explain this to me in plain English if you can. I ...
1 vote
113 views

### How do you solve any partial differential equation using equivalent circuits? How is this possible?

Here's the quote from this wiki: In 1945 Kron suggested an approach to Schrödinger's equation with networks. The same year he used equivalent circuits to solve differential equations. So I've been ...
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### Modified Bridge full wave Rectifier output [migrated]

In the circuit diagram of the full wave rectifier given, if a diode D is connected between points X and Y, would the Output Voltage vs Time graph be different from that of the unmodified diagram?
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2k views

### Does a Mobius resistor have zero inductance? How would you calculate the inductance?

Wikipedia describes a Möbius resistor as follows, and the Patent for this device gives a similar description. A Möbius resistor is an electrical component made up of two conductive surfaces separated ...
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2k views

### Why is it easier to raise AC current to high voltage than DC?

In my country (and maybe all around the world I don't know) once electricity has been generated, it is then raised to 200k Volts for transportation. I know this is to reduce the loss. Given $P=U.I$ ...
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25 views

### Actual power consumption of an irregular measure (GPU/CPU) [closed]

Hello and my apologies if this is off-topic or really too basic. My math and physic days are really far far away.... I want to measure the energy consumption of both the GPU and CPU of a computer ...
1k views

### Gravity train with the help of batteries?

Imagine a gravity train (https://www.math.purdue.edu/~eremenko/train.html) that goes through Earth's crust from point A to B. The train could advance through the ride just by the force of gravity and ...
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### What is the relationship between Diode Junction Current and the Fermi-Dirac probability function?

The equation for the Fermi-Dirac distribution function is $$f(E)=\frac{1}{e^{(E−E_F)/k_BT}+1},$$ and can predict charge neutralization. How is this applied to a diode's junction current and can this ...
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1 vote
34 views

### Comparison of 2 fans [closed]

I have 2 20" box fans. The first fan draws .65 Amp and claims 1780 CFM. The second fan draws .45 Amp and claims 2300 CFM. The fans are new, and the electric motors are of similar design, so I ...
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150 views

### Deriving an lumped element LC circuit as the limit of a resonant cavity mode

In principle, an LC circuit is just a degenerate limit of an electromagnetic cavity, where the frequency $\omega_0$ of the resonant mode is much lower than the inverse size of the cavity. As a result, ...
• 96k
37 views

### Where is the excess energy going to when a solar inverter is operating a photovoltaic (PV) panel away from the maximum power point (MPP)?

The MPP is the maximum power point of a solar panel and a PV inverter will typically try to find this MPP to yield the maximum energy ouput. But sometimes it might be neccessary to operate the panel ...
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29 views

### What textbooks would you recommend to learn quantum systems engineering?

I am a first-year undergraduate doing a BA in Physics. I have studied quantum mechanics at the rudimentary level, and as far as my mathematical background is concerned: I know linear algebra and ...
114 views

### Is there a guiding principle to determine when quantization is needed when modeling EM-matter interactions?

I'm an undergrad engineering student and I need some guidance to help me understand a few issues regarding classical electromagnetism (EM). I'm interested in engineering applications where there is an ...
1 vote
28 views

### Understanding alpha and beta factors in transistors

I am a student and this is first time we are introduced to semiconductors. During studies I learned about the alpha and beta factor in a transistor. Actually I was doing some numericals were I got ...
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49 views

### What could be the cause of a limit in the voltage supplied to a capacitor?

Recently I built a very basic 2-stage coil gun for a school project. Each coil was powered by an electrolytic capacitor. In order to charge the capacitor, the coil connected to an IGBT (insulated-gate ...
1 vote
83 views

### Trouble understanding physics behind MOSFET body effect

I’m struggling to understand why a negative voltage applied to the bulk contact of an n-type MOSFET increases the threshold voltage. I can see why it happens due to the equations, but I can’t wrap my ...
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49 views

### What is the application of differential equations in electrical circuits?

I understand the derivation of the resistor, capacitor and inductance but then what is the practical usage of this derivatives?
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### What can I give as an example for a dumb instrumentation system? [closed]

I've searched through many websites and textbooks but none of them have given an example for a dumb instrumentation device.
1 vote
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### Why are most solar panel rated at 12 volts or 24 volts? [closed]

Most solar panel come in 12 volts or 24 volts, why?
53 views

### Is it possible to create a laser pointer with adjustable beam width?

Is it possible to create a (line) laser pointer with adjustable beam width? I mean instead of having a dot laser pointer, create one where one may press a button to switch from 10m line beam to 5 m ...
28 views

### If loads are perfectly balanced, and line resistances are zero, is ground wire redundant?

Here is my understanding of neutral and ground: The return current through the neutral wire is the vector sum of three phase power. If loads are perfectly balanced, the vector sum is zero, and the ...
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54 views

### Is this actually a Group II, Group IV transistor? What should its properties be?

This question is for more than a theory. I would like to disprove that what I'm working on is not a Group II, Group IV transistor. I know they CAN exist. I don't know why they don't exist or what ...
38 views

### Can you use the water flow exiting a hydroelectric generator to generate more energy?

In videos of hydroelectric generators I often see that the water that exits a turbine is still moving with significant velocity. Example of a turbine that has exit water flow with significant velocity:...
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### Is there any difference between charge-transfer insulator and conventional (band) insulator?

Like conventional (band) insulators, is conductivity in the charge-transfer insulator blocked by the Pauli exclusion principle?
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1 vote
68 views

### Uncertainty of output current in voltage-current converter

I have a problem comprehending some things about uncertainty in electrical measurements. Here is illustrative example from my textbook. We use voltage-current converter for measurement. U1 = 10V, I2 =...
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### Physics basics of junction termination structure (JTE)

I have come across two books that try to explain how a junction termination structure work (low doped implant of the same type as the cathode/anode depending of the substrate type). Both books explain ...
39 views

### Penning Trap Anode

I am looking to confirm my logic around how the anode in a Penning trap is able to reflect/contain protons via an electric field. My logic is that the anode is an excitinged metal such as (Metal)2+, ...
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### Conceptual doubt about voltage drop in a diode

In the given circuit, I am not sure how to solve it, I know that due to the current the diode is in reverse bias, hence no current should flow through it, But the answer is not given that and a finite ...
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226 views

### Lamp specifications

So when a lamp has a specification of 24 V, 5.0 W, does it mean that it requires at least 5.0 W to work? Can it still consume more power? Or would it then fail? If for example a power supply has ...
1 vote
64 views

### Does voltage limit the magnetic force of a coil?

My question I had is whether it is strictly current that creates the magnetic force in the coil or if voltage is also relevant? The reason for this question is because I figure if it is just current ...
6k views

### How do headphones and earphones produce good bass if tiny speakers can't produce low frequency sounds very well?

It's a well known fact that small/tiny speakers cannot produce low frequency sounds very well. Conversely, large speakers cannot produce high frequency sounds very well. Hence the need for tweeters ...
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1 vote
100 views

### Does a low resistance make it difficult to run a generator?

Imagine I have a simple AC generator. I am providing energy to rotate the coil, which converts this to electrical energy. If I connect the ends to an electrical component such as motor, bulb, the ...
37 views

### How does electrical energy in parallel work out?how does less energy travel through more resistance,and lose the electrical energy which it not had? [duplicate]

Before asking my question,I want to talk about certain points 1.Lets suppose there is a battery of 12 volts,this means that the potential difference between the negative and positive terminal of the ...
42 views

### What happens during under-modulation?

I need clarification regarding what exactly happens to the information in amplitude modulation if it is under-modulated. I know that if it is over-modulated, some information will not reach the ...
1 vote
104 views

### Rigorous book (or other materials) on Circuits, Electronics etc

What I usually find in a typical book on these topics is the following structure: "Here is the theorem/fact/formula, here is an example - now go ahead and apply this to some trivial problems that ...
91 views

### How to model the state space matrix of a pendulum?

Here's an image of the problem: I'm trying to put the following problem in matrix form (state space) but I don't know how would I put -(g/L)sin(x1) in the A matrix since the x1 value is inside the ...
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1 vote
39 views

### Why is the relation between voltage ratio and frequency a linear one in a lumped transition line?

In an experiment the cutoff frequency of a lumped transmission line is determined by measursing the ratio of the output/input voltages. The lumped transmission line is a ladder network of 40 ...
• 1,027
1 vote
77 views

### What is the relationship between driving point resistance and Thevenin resistance?

Thevenin Theorem A linear, active, resistive network which contains one or more voltage and current sources, can be replaced by a single voltage source $V_T$ (the Thevenin voltage) and a series ...
1 vote
125 views

### What is a realistic value for the internal resistance of an ammeter?

As I understand, ideally an ammeter will have zero resistance as it is connected in series with the circuit and so there will be no potential difference across the device. However, in reality there ...
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1 vote
76 views

### How do electrons flow in a "random single wire antenna" of a Raspberry Pi, which is DC and just have one path? (no gnd)

I have been amazed by the fact that just by inserting a cable in a GPIO of the raspberry pic acts like an antenna, as far as I know, electromagnetic waves are generated when there's current, and also, ...
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198 views

### Why does current reduce in step up transformer?

I have researched about it and found the laws everywhere as if lawyers have written those answer. I know the law of conservation of energy, but I don't want to think like a lawyer, I want to think ...
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145 views

### Which electric power transmission line has more losses an AC or a DC?

For the same generated and transmitted RMS value of power from an electrical power plant station, which transmission line used, assuming having the same wire specification (i.e. wire material ...
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