All Questions
Tagged with electric-circuits power
173
questions
-1
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0
answers
53
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Powerlines in Asian villages are they safe? [closed]
Powerlines in Asia - I have seen lots of lines wound up or passing through bushes. Is this dangerous? How does this work?
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0
votes
6
answers
136
views
What is electromotive force? What's its relationship to Voltage? + clarification of confusion
So first of all, yeah I know that the electromotive force is not a force (the name was coined by Alessandro Volta I think).
About Power and dissipated power
The power with wich a battery provides the ...
- 11
0
votes
2
answers
42
views
How is power dissipated proportion to current and current squared?
$P=IV$ and $P=I^2R$. Does this mean that $P$ is proportional to both $I$ and $I^2$? I don't understand this concept. And when should I use the various formulas for power? When another variable is ...
1
vote
1
answer
49
views
Calculating the efficiency of a solar cell based on the wattage of the lamp powering it [closed]
I am working to characterize some solar cells I have access to based on their material structure by measuring the IV curve of the cells. I can generally compare the cells by comparing their $P_{max-...
0
votes
1
answer
28
views
Bulb glows full brightness at which time of $I$-$t$ graph? [closed]
I know that for first question,resistance increases..
In second question,it is asked to find the power when bulb glows at full brightness,
I think it is NOT 1A*200V=200w
What i think is that,we should ...
1
vote
2
answers
75
views
Calculating mechanical power of an electrical motor
The total power of a powered drill is 850 watts (the rated value written on the drill's casing) and the current at the supply voltage of 230 volts is 3.7 amperes according to the formula $I = P/U$. ...
0
votes
1
answer
37
views
Derivative of formula for battery's output power is not right
There is something about output power of battery in circuits that bothering me.
I hope you help me.
So we know the formula for power in electrical circuits is (current x voltage) or:
$$
P=IV
$$
and ...
- 3
0
votes
1
answer
81
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Why is bandwidth not centred at resonant frequency in LCR series circuit?
When we calculate lower and higher frequency such that power becomes half in LCR circuit we end up with two value.
For a complete derievation please see here.
I have copied relevant information below:
...
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3
votes
1
answer
266
views
Is power of a battery constant?
In my question I'm neglecting the impact of discharging.
I'm trying to make sense of Watt's law: $$P=IV.$$ I always thought that the voltage and the power of a battery were constant features that ...
-1
votes
2
answers
141
views
Energy lost in a resistor and its temperature
The power lost across a resistor is proportional to the square of the voltage drop across it. This means by increasing the voltage across the resistor, the energy lost in it in a given time grows non-...
0
votes
1
answer
58
views
Power delivered to a Resistor is $V^2/R$. Does size of battery matter?
I had connected a thin Resistor wire to series combination of six coin cells or to a small sized 9V battery. The wire got hot in a normal way BUT when I connected the same resistance wire to a large ...
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0
votes
3
answers
169
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Why is Power in an electric circuit equal to $VI$? [closed]
Where did this formula come from? Everyone I asked just told me to substitute values of in ohms law to derive this but no one told why is power equal to voltage * current. Part of the reason for this ...
- 9
0
votes
2
answers
49
views
$I²R$ loss in case of transformer
Suppose we have a 100 V A.C. supply, and we connect a 1 ohm resistor with it. Now the current through the resistor will be 100 A. Now we connect a 1:2 step up transformer with the A.C supply, and then ...
- 11
0
votes
0
answers
27
views
Why are partial derivatives of Energy and Co-Energy with respect to x opposite numbers?
In a system where the flux linkage $\lambda = \lambda(x, i)$ is a function of dispalcement $x$ and current $i$.
Its energy is defined as
$$
W = \int_{0}^{\lambda} i(\lambda', x)d\lambda'.
$$
Its co-...
0
votes
0
answers
41
views
Does $P=VI$ contradict $V=IR$? [duplicate]
Imagine there's a dam generating power (P) that needs to be transported 100km away. Engineer Pedro suggests increasing the voltage to reduce current acording to P=VI, while Engineer Juan suggests ...
