All Questions
Tagged with electricity electrical-engineering
69
questions
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
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
2
votes
1
answer
65
views
Does it cost more energy to turn on a CFL globe than it is to leave them on?
Say there is a 15 W CFL globe.
When turned on for an hour, it consumes electricity worth $10 in terms of energy consumption (made up cost for simplicity). If the occupants of the room periodically ...
- 147
2
votes
2
answers
339
views
How do you model the resistance across a symmetric sheet of plastic, streched (think ceran wrap) between a circular anode and cathode?
Here is the problem. You need to model the resistance across a circular sheet of polypropylene (plastic). The resistivity of polypropylene is 1E15 Ohms per meter. The expression for resistance on a ...
- 170
2
votes
1
answer
946
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Electrical flow in a simple parallel circuit
I'm having trouble understanding something in one of my text books:
Let’s have a look at the implications of each circuit configuration.
Figure 3.13 shows the Conventional representation of a ...
- 207
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
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 ...
2
votes
0
answers
662
views
Why does this magnetic charger cause short circuit when it sticks to the metal leg of my table? [closed]
Recently, I have bought this product. It is basically a USB cable, with a magnetic end, and a tiny attachment that goes into the mobile device.
I plugged it into my laptop cooling stand (which has ...
- 121
1
vote
3
answers
15k
views
Calculating time for a fully charged UPS
I have a UPS of 1000 Volts connected with 2 batteries each of 150 Amp. How much time it will take to consume the whole UPS (after fully charged) when a device of 1Amp is getting electricity form that ...
- 149
1
vote
3
answers
3k
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Why does a charged particle in a cyclotron moves in circular path?
Force on the particle is charge*(velocity×magnetic field intensity).
The magnetic field intensity is perpendicular to velocity of charged particle.
What is it that makes it move in a circular path?
- 55
1
vote
1
answer
440
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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
1
vote
2
answers
116
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When heat loss is more than energy generated [closed]
Suppose a electric power station produces 200W of electricity @ 200V. Now instead of stepping it up, it decides to transmit it as 200V to a city 20 km away. The transmission cable has resistance per ...
1
vote
1
answer
105
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
1
vote
1
answer
775
views
How Equilibrium is Reached and Voltage Shared in a Series Circuit with Two Resistors [closed]
I've been reading up on basic electronics recently and to help me understand things better, I've been writing down my understanding of what I've read in layman's terms. One thing I've struggled with ...
- 11
1
vote
1
answer
100
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Why current of a battery drops continuously in high currents?
I have asked this question on EE SE but could not get a satisfactory enough answer.
I have shorted an AA battery through an ammeter. Inititially, the current reading on ammeter was around 0.9 amperes ...
- 131