All Questions
Tagged with electricity electrical-engineering
66
questions
5
votes
2
answers
135
views
What is the "closed circuit" of a bug swatter racket?
There are bug swatter racket that can kill fruit flies, mosquitos, or flies, if the insect touches the metal mesh.
However, when I look at the construction of the device, the metal mesh is all one ...
- 151
2
votes
1
answer
185
views
What can cause a spot above my WiFi router's antenna? [closed]
Lately a weird dark spot has appeared right above the antenna of my wifi router. It wasn't there before.
I have tried to wipe it and it got a little bit brighter but I don't think it's dust.
My guess ...
- 21
2
votes
0
answers
96
views
Why Faraday homopolar generator need brushes?
It is said that if one would attach a load physically to the rotating disc from center to rim no current would flow because both in the load wires and the disc itself currents would be generated in ...
1
vote
1
answer
104
views
If a downed powerline contacts the metal chassis of my car, can I touch any metal parts of my car while sitting inside of it?
consider the following situation. I parked my car underneath some high-voltage lines – let’s say 380 kV-lines. Suddenly, one of the lines breaks in the middle due to a storm and one end of the (still ...
- 11
0
votes
1
answer
68
views
Current flow with no resistance
Imagine a simple circuit consisting of a battery with potential $V$ connected to a resistor with resistance $R$ by a loop of copper wire with $0$ resistance. It is obvious that a current $I=\frac VR$ ...
- 366
0
votes
2
answers
91
views
What's the proportion of energy received on an overloaded generator?
I'm trying to understand the underlying physics with how generators work. I found this question which had some interesting answers, but it does not include all the details I'm after.
Suppose I have a ...
0
votes
1
answer
38
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, ...
- 4,515
9
votes
5
answers
4k
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 $P=U.I$ ...
- 201
1
vote
1
answer
433
views
How do devices control how much power they use?
In power systems (Australian for reference) the grids run at a constant voltage of 220V. I’ve heard of switches were less voltage being used is created by adding more resistors for example to dim ...
- 43
2
votes
3
answers
147
views
Electricity supply in homes is AC but what about rms value that has only one direction? [closed]
In our homes, electricity supply is AC.but we have rms value in our homes...How do they relate? Is rms value generated in transformer or what??
- 21
0
votes
0
answers
75
views
Ramsauer–Townsend effect and Thermal Runaway in Thyratrons / (vacuum tubes)
A few years ago an EE told me that the Townsend effect was involved in thermal runaway within vacuum tubes. I can't seem to find any specifics on this on the internet. Can anyone disprove / verify and ...
- 23
2
votes
2
answers
47
views
Why do the two relations of Power in a resistive load $P= I^2 R$ and $P = V^2/R$ (Assume Ideal resistances ) seem contradicting in this situation?
I have seen similar questions in the forum but they fail to be very specific .
I would ask the question from the viewpoint of Problem Solving. Let me put this question from a textbook :
A heater coil ...
- 27
0
votes
0
answers
25
views
Do you get correct graph of transfer characteristic, if you take +ive Vds(constant) value instead of -ive. As mostly CNTFETs are p-chnl FET
I'm studying transfer characteristic curve of CNTFET to get value for mobility, S.S, etc. According to my basic background knowledge, NMOS curves lie in the 1st quadrant. While for PMOS they lie in ...
- 11
5
votes
1
answer
143
views
What is causing the acceleration of charges in an ideal TEM transmission line?
As I understand, in an ideal TEM transmission line we can set up the telegrapher equations and solve to show that the line propagates voltage and current waves.
My confusion arises when we recognize ...
0
votes
2
answers
170
views
What is the difference between horizontal units and horizontal scale at an oscilloscope?
This is a picture of the data of a given measurement by an oscilloscope. I would like to know what the difference between horizontal units and horizontal scale at an oscilloscope is. I would be so so ...
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