4
votes
EMF being equal through KVL
The mistake you are making is trying to connect two ideal batteries $V_2$ and $V_3$ with different EMFs in parallel, winding up with the inconsistency of having two different voltages in parallel, ...
- 55.6k
3
votes
Accepted
How can this circuit be simplified in the first moments after the circuit breaker closes?
In a transient problem like this, to determine the initial conditions for the problem after an ideal switch changes state, we treat inductors as current sources and capacitors as voltage sources. The ...
- 22.8k
2
votes
Voltmeter reading in a bridge circuit
Instead of presenting a solution, I'd like to point out where you're going the wrong way.
You're talking about "the" resistance and "the" current, as if there were only one ...
- 2,048
2
votes
Accepted
How is there current if there's no voltage?
A real am-meter (like the one on your desk) has a very small
resistance $R$ (may be $0.001\ \Omega$).
The current ($I$) trough your am-meter and the potential difference
($V$) across it are related by ...
- 25.7k
2
votes
How to understand the model of electric current and potential in circuits?
It is not the electrons themselves that carry the energy in the circuit. They do not gain any energy overall in the battery, and nor do they lose any in the resistor, overall.
The electrons undergo ...
- 56
2
votes
Accepted
Is there a contradiction at the top of this circuit?
If what is asked is V on the left, you may assume an ideal voltmeter drawing zero current. Then, your circuit is a big loop producing a voltage but zero current. The big loop is composed of 5 things ...
- 3,269
2
votes
Why is lamp D off?
The left and right lamps, and the left and right cells, are identical. So the voltage drop across the lamps will be the same, and the voltage between the outer lamps will be the same as the voltage ...
- 397
1
vote
How can this circuit be simplified in the first moments after the circuit breaker closes?
Ammending the correct answer of Photon. This has to do with the capacitive and inductive electric reactance in your presented circuit. Capacitors resist sudden changes in their voltage (including a ...
- 3,011
1
vote
Is there a contradiction at the top of this circuit?
Loop analysis necessitates a singe value of loop current. Just like node analysis necessitates a single value of node voltage. In your case, you are getting two different values of current in each ...
- 55.6k
1
vote
Is there a contradiction at the top of this circuit?
The circuit may be feasible if the circles represent power supplies (constant current or voltage) rather than meter readings.
- 11.4k
1
vote
Instantaneous current and average current
Not really, because of shot noise (due to electric charge localized on particles and discretized into multiples of $e$) and thermal noise (due to random thermal motions of those particles).
In your ...
- 27.8k
1
vote
Instantaneous current and average current
is the instantaneous current also same throughout the circuit?
Yes. For most practical purposes, the instantaneous current is the same throughout a simple (unbranched) circuit.
And why?
The current ...
- 2,696
1
vote
Does speed of electrons decreases when they pass through resistance?
In classical theory, the free electrons are in thermal equilibrium with the atoms of the conductor, but are accelerated between collisions by an electric field. The result is a low “drift” velocity. ...
- 11.4k
1
vote
The Resistance in an electric kettle
The parallel combination of the two Ro resistors is 1 ohm. If there was no resistance R and your kettle were connected to a 120 vac outlet with both switches closed, if would draw 120 Amperes or 14,...
- 55.6k
1
vote
Accepted
$V$-$I$ characteristics and circuits
The slope of the $I\ \text{against}\ V$ curve gives the reciprocal of the so-called 'slope resistance', $\frac{dV}{dI}$. This can be a useful concept, but it's not relevant here.
Here are some hints ...
- 27.8k
1
vote
Confusion about electrical potential difference
I'm not sure if I understand your question correctly, however I assume your talking about the potential difference across each of the 2 distinct paths being constant. You can think of it as "...
- 3,705
1
vote
Accepted
Confusion about electrical potential difference
The energy loss of a specific charge (like an electron) on passing through a resistor depends not on the resistance, but on the voltage difference. That voltage difference itself depends on the ...
- 33.7k
1
vote
Voltage and series circuit
In a series circuit, the voltages are different when the resistances are different If $U$ is the total voltage across both resistances, the drop over the fist one will be $U_1=\frac{R_1}{R_1+R_2 } U$ ...
- 1,157
1
vote
Impedance of an LCR circuit
I thought that to calculate impedance over parallel components I had to take the product of the impedances of each 'side' (here meaning just the product of the inductor's and capacitor's impedances) ...
- 415
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