The electric-circuits tag has no wiki summary.
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2answers
541 views
Relating milliampere-hours to watt-hours for batteries
I've seen many batteries that are measured in milliampere hours (mAh), while others are measured in watt hours (wh). How can I convert them between each other so that I can actually compare them? It's ...
9
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3answers
304 views
Current in a simple circuit
I was going over my notes for an introductory course to electricity and magnetism and was intrigued by something I don't have an answer to. I remember my professor mentioning, to the best I can ...
0
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1answer
193 views
What is the role of center-tapping in a full wave rectifier?
Note: I have already tried googling. Although similar questions have been asked on different forums, I couldn't find a detailed explanation, which I could really understand.
Circuit diagram ...
12
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2answers
1k views
The “Nerd Sniping” problem. Generalizations?
This question is motivated by this xkcd comic strip
.
The problem is indeed interesting, and my first recollection upon reading this was a similar problem in the book Problems in General Physics by ...
1
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3answers
86 views
Capacitor Charging and Discharging when connected to the ground
When we charge a capacitor using a battery and then remove the battery, the plates of capacitor becomes charged. One holds positive charge and the other one gets equal negative charge. o. k. ?
Now ...
1
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1answer
2k views
Current against the inverse of resistance graph, $I = V/R +c$
If I have a plot of current ($y$ axis) against 1/Resistance ($x$ axis).
The circuit it is measured from is a simply 2 resistors connected in parallel to battery, where the potential across the ...
1
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2answers
50 views
Different batteries connected in parallel
If we have 2 batteries one of emf x and the other is of emf y and we connect them in series we get an effective emf of x+y.
But what if we connect them in parallel, how to calculate the emf now?
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2answers
397 views
Why does the light bulb's brightness decrease?
The book said that the brightness of R1 would increase and R2 would decrease. I don't understand this at all.
Why does adding a wire from b to c change anything to R1?
Shouldn't charge still flow ...
0
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1answer
119 views
Physical explanation for capacitive circuit
In capacitive circuit, the voltage and current are out of phase. the current leads the voltage by 90 degrees. this can be explained by these two equations:
$$V = V_{\max} \sin \omega t$$
$$I = ...
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7answers
1k views
Cyclist's electrical tingling under power lines
It's been happening to me for years. I finally decided to ask users who are better with "practical physics" when I was told that my experience – that I am going to describe momentarily – prove that I ...
4
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2answers
941 views
Strategies against 50 Hz mains hum on detector signals?
I'm having problems with a strong 50 Hz mains hum on signals created by photodetectors. I assume that they are due to ground loops and I realize that the best option would be to remove those. What are ...
2
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1answer
154 views
Positive test charge
Protons have positive charge on them. Protons aren't mobile. So how can a positive test charge move from the negative terminal of a cell to the positive terminal and gain electric potential energy? ...
2
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2answers
184 views
Is equivalent resistance always lower if we add a resistor to a passive electronic circuit?
How to prove that equivalent resistance of any passive network is always lower if we add a resistor between arbitrary two nodes?
Note that this is not necessarily a parallel circuit, 2 nodes that we ...
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3answers
330 views
Is this really how a capacitor works? Why doesn't it behave like a resistor?
My book says a capacitor is two conducts being connected by an insulator. Now let's take a parallel plate capacitor to simplify the problem I have.
Suppose I got two parallel plate capacitor in ...
3
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1answer
374 views
General integral to find resistance
My question is: is there a simple and truly general equation for the resistance between two electrical equipotential surfaces?. Obviously, if so, what is it, and if not, why? It would be very ...
2
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3answers
2k views
Wheatstone Bridge
Why is using a Wheatstone bridge such an accurate way of calculating an unknown resistance? What are the benefits of using it over Ohm's law?
It seems that it has something to do with the wires ...
2
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1answer
636 views
Current from induced emf
If the induced emf in a circuit is negative, and current from this emf is the emf over the resistance, what happens to the negative sign in the induced emf when solving for the current? Surely there's ...
1
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1answer
980 views
How to calculate the charge and the potential across a charged capacitor charging an uncharged capacitor?
Initially, there is a single capacitor $A$ attached to a power source that charges it to a certain voltage $V$. Once it is charged, it is instantaneously removed and placed in a circuit with an ...
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0answers
57 views
Capacitors discharging in series [duplicate]
If you connect positive plate of a charged capacitor to ground, it doesn't get discharged. Now consider $4$ capacitors of equal capacitance connected in series to a $10\, \mathrm{V}$ battery. Connect ...
0
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1answer
82 views
measuring electromagnetic induction
There is a famous law which says that a potential difference is produced across a conductor when it is exposed to a varying MF. But, how do you measure it to prove? It is quite practical.
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1answer
74 views
Weird circuitry problem [closed]
I should note that I am asking these questions on behalf of a friend who claims to be too busy. Anyway here is a circuitry problem:
Why is C the correct answer?
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3answers
432 views
Parallel or series connection?
Are C1, C2 and C3 connected in parallel, or C2, C3 in parallel and C1 in series with C23?
Btw it appeared as a question in the basic physics Albanian A-levels yesterday. You had to find the ...
0
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3answers
671 views
Direction of Magnetic force from a current running through a coil of wire
What is the direction is the magnetic force vectors pointing from a coil of wire that has current running through it?
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