An electronic system, with closed loop current flow, and relative electrical potentials present across electrical components.

learn more… | top users | synonyms

0
votes
2answers
23 views

Voltage across voltage source in a short circuit

When we short-circuit a voltage source, the current will be very high. The voltage across the wire is 0V. If we apply KVL, also the voltage across the voltage source is 0V. How can it be 0V if we have ...
0
votes
2answers
33 views

Ohm's law experiment

I was going through my physics laboratory manual. In the Ohm's Law Experiment, the book states a few precautions without any reasoning. 1.The wire whose resistance has to be determined should ...
1
vote
1answer
33 views

Calculation Equivalent Resistance In A Circuit With resistances connected in a circle [on hold]

I am having trouble in finding the equivalent resistance between the terminals 'a' and 'b' in the following circuit: Please can anyone explain to me how to solve such problems. Thank You!
1
vote
1answer
22 views

Why is a series resistor needed in a simple thermistor experiment? [on hold]

I have come across the following simple question, however I can't see any need for a fixed resistor in series. The only possible reason that I can think of is that the resistance of the thermistor ...
3
votes
1answer
39 views

Why does energy flow between a high voltage transmission line and linemen approaching it on a helicopter?

The video High power line workers shows linemen servicing a live high voltage transmission line. As the helicopter approaches the line, the lineman reaches out with a metallic wand that is ...
2
votes
0answers
25 views

How to control a dc motor? [on hold]

I am in 8th standard and I am doing a project on 3d printing pens. I want to know how to control a dc motor, so that when I press a button it should increase its speed gradually till it reaches its ...
0
votes
0answers
20 views

Dielectric Constant and Frequency [on hold]

How dielectric constant of a parallel plate capacitor varies by varying frequency in physical terms?
1
vote
4answers
66 views

Voltage of a battery in a circuit with an infinite resistance [on hold]

I have a dilemma that I would like to share with you concerning batteries (without neglecting internal resistance), emf and resistance of a circuit. To better visualize my question you may need to ...
-3
votes
0answers
21 views

relation between permittivity and IMPEDANCE? [on hold]

DETERMINATION OF Permittivity FROM IMPEDANCE MEASUREMENT USING AGilent ANALYZER
1
vote
1answer
30 views

Help to solve a circuit with capacitor and resistor

Till now I'd never solved a circuit with resistor and capacitor. I'd seen the problem and tried to solve. But now I am in a doubt.The circuit was like that- My attempt-
-5
votes
0answers
65 views

Resistance is given as mentioned how will we find the equivalent resistance dnt think anyone can do it [closed]

it is a electric circuit do we have to use ohms law for this question if yes how will we do it
-2
votes
1answer
56 views
0
votes
0answers
16 views

Ampere's circuital law and Maxwell's correction based thought experiment [on hold]

I just learned about Maxwell's correction in Ampere's law, when he realised that there is a magnetic field near a capacitor even if there is no current. I was wondering about other possible ...
0
votes
1answer
19 views

How do I show for an ideal transformer $M^2=L_1L_2$?

I've been stuck on this problem for about an hour. In an ideal transformer, the same flux passes through all turns of the primary and of the secondary . Show that in this case $M^2=L_1L_2$, where ...
0
votes
2answers
25 views

Using resistance

I want to know the purpose of using resistance. Is it used to Reduce the amount of current? Reduce the speed of the electrons in the wires? For the first reason: Why do we just don't use a ...
0
votes
1answer
28 views

Resistance in A.C. circuits

Why do electromagnets offer maximum resistance in A.C. circuits?
1
vote
0answers
25 views

Determining initial voltage across a capacitor [closed]

This one has got me stumped. I have a graph of voltage vs time and a corresponding power vs time graph. Taking the integral of the power vs time graph gives me the work done on the capacitor. Now the ...
2
votes
1answer
81 views

Resistor Puzzle [closed]

I was going through physics competition problems on http://fykos.org/ when I stumbled across this one: ... The Square The Joker The electric circuit in the image is made from the infinite ...
3
votes
2answers
71 views

How do radio antennas follow electrical rules

Power = current times voltage. However current requires a complete circuit to 'flow'. How can a 1,000 Watt antenna work if the output of the transmitter is connected to a single emitting wire or ...
-3
votes
1answer
40 views

What happens when the switch in this circuit is flipped? [closed]

what would happen to lights A and B if the switch in this circuit is flipped?
1
vote
0answers
15 views

How to apply kirchoff's laws to motors in DC and AC settings

DC case: is it ok to treat a motor as a variable resistor, with resistance depending on the load? AC case: suppose I have a motor that runs at 120V AC and is rated to X watts, how can I determine how ...
1
vote
2answers
44 views

Some questions related to circuits and flow of electrons

I have some doubts related to electric fields and flow of current. So, let us assume an electric circuit, which contains a battery and a wire connecting positive and negative terminal of the battery. ...
1
vote
2answers
35 views

Sign of induced EMF and other elements in AC circuit

I am having problems to determine the direction of the induced EMF in AC circuits. For example, we have an inductor of inductance $L$. The induced EMF is given by: $$ \epsilon = - L \frac{di}{dt} $$ ...
1
vote
0answers
25 views

Electric circuit for nonlinear pendulum?

Is it possible to make an electric circuit analogue of nonlinear pendulum? To model the equation $y''=sin(y) $. They did this on analog computers in the past, how? How to model sine-nonlinearity?
2
votes
2answers
77 views

How to calculate the resistance of a resistors in a grid?

I've found a lot of example of a grid where you want to total resistance of a grid. My problem is different. Let's say you got a grid of resistance (3x3) but you only have the total resistance between ...
0
votes
2answers
48 views

Input Resistance vs Output Resistance

I am having trouble understanding the difference between these two concepts. I know that input resistance is the resistance as seen by the input terminals and output is as seen at the output ...
1
vote
0answers
20 views

How do electrons choose their way through nodes? [duplicate]

Suppose I have a circuit, powered by some emf ($V$). If I put two resistors $R1$ and $R2$ of different resistances in parallel, the current at the node is divided following Kirchhoff's circuit laws. ...
0
votes
2answers
41 views

Kirchoff's law, can it tell me the direction of current in this case?

Say I want to find the current Ia in the circuit below: If I use the approach of using kirchoff's voltage law and ohm's law on the left loop, I get $-24V -12k\Omega*1mA -21k\Omega*I_a = 0$ $I_a = ...
-1
votes
1answer
19 views

How can power factor be improved by using a capacitor in an LCR circuit?

First of all what is even meant by improving power factor? My book says we can improve power factor by making impedance tend to resistance I.e. Z-》R, and then they say that power factor is improved by ...
1
vote
1answer
25 views

Circuit energy evaluation

I saw in a documentary that given a circuit, the electron comes out of the negative side of the battery with some electrical potential energy and upon passing through a resistor it gives up all its ...
0
votes
0answers
28 views

How to figure out if an element in a circuit is absorbing or delivering power?

. Eg: In the above circuit. 50v source and 0.2Va current source is said to absorb power.If power is absorbed,what work is done with the absorbed power.
0
votes
1answer
32 views

what is the function of Current Source in a circuit?

The voltage across current source is due to current itself or due to the circuit within which it is present.
-1
votes
1answer
46 views

What is the condition for resistance in the branch to be parallel [closed]

What if the incoming current at one node not equal to the other, does the resistance in branch still parallel. Eg: In the above circuit diagram how is 17.5 Ω resistor parallel with 5Ω and 2.5Ω ...
-1
votes
1answer
26 views

Circuit current direction [closed]

Can someone explain to me why the direction of the arrows are drawn the way they are in the electric circuit in the picture.
2
votes
2answers
34 views

Electrical injuries - Doorknob vs powerline

This is something that has bothered me since high school physics. I have a medical and engineering degree, yet I can't for my life answer this question in a way that's logically consistent in my ...
1
vote
1answer
63 views

What's the purpose of capacitors in parallel

In my school textbook it is written that the capacitor acts as a filter, that is, it decreases the fluctuations in the potential difference across the load. But since all the components are ...
1
vote
1answer
37 views

electric field's area [closed]

How much area an electric field surrounds? since we're just able to draw the electric lines of force we sometimes think that the field is though 3d but surrounds a finite area.But is it measurable or ...
2
votes
3answers
79 views

What changes in the electrons before and after a voltage drop?

It is easy to visualize gravitational potential energy as a function of the position of height, and a change in this potential is manifested in a change in height. Further, by the work-energy theorem ...
3
votes
1answer
56 views

Effective resistance across 2 adjacent vertices of a dodecahedron with each edge $r$

What will be the effective resistance across 2 adjacent vertices of a regular dodecahedron (12 faces) with each edge having resistance $r$? Here is the source for the problem, it's problem 20. on ...
2
votes
1answer
45 views

Problem with differential equation RLC circuit serie [closed]

I am trying solve the differential equation of RLC's circuit in serie, I have: $C=4\ F, L= 1\ H$, $R=5\ \Omega$, and $V_e=20\ V$. $1)$ first I got the equation, it is: $i''+5i'+\frac{1}{4}i=0$, what ...
2
votes
1answer
36 views

Do resistors have internal energy?

I was reading about LC Oscillations in my book and came upon this: In actual circuits,there is always some resistance and some energy is therefore transformed to internal energy. Why internal ...
1
vote
2answers
30 views

Why does current density changes but not current? [closed]

let us assume that we have a conductor with a specified resistance ( case 1 ) and a normal conductor ( case 2 ) as shown in the figure , and now we apply an external electric field with a battery on ...
0
votes
0answers
20 views

Potential difference across a resistor

I would like to know if the potential difference between the two ends of the resistance is same as the potential difference between any tow points in the resistance whose length is smaller than the ...
0
votes
1answer
40 views

Electric field along a wire and load

I have referred to many books and all of them apply loss in potential across a resistor only in case of circuits. However, the electric field is present in the whole conductor. Hence the electrons ...
-1
votes
1answer
48 views

Resistors in parallel - Written description of a circuit - drawing needed [closed]

I can't visualise what this circuit looks like from the description Three identical resistors are connected across a potential difference V so that one of them is in parallel with the other two ...
0
votes
0answers
23 views

How do the voltage rises balance with the voltage drops in this example of a series circuit?

Consider a resistor and a capacitor in series, with the capacitor initially charged. There is a conservative electric field in the circuit, so $$\oint \vec{E}\dot{}d\vec{l}=0,$$ which gives $$\int_a^b ...
0
votes
1answer
13 views

How to compute the charge as a function of time in a simple C-L circuit

I am trying to compute $q(t)$ in a series circuit consisting of a capacitor of plate charges $q_0$ and $-q_0$ and an inductor. The switch is closed at time $t=0$. By Kirchoff's Law, ...
0
votes
0answers
27 views

References on Josephson ring modulators

I would like some good references on Josephson junctions and, in particular, Josephson ring modulators. I know that Devoret has written a handful of papers and notes on JJs, but I am hoping to find ...
1
vote
1answer
83 views

Distribution of surface charges in an electric circuit

I'm reading Sherwood and Chabay's brilliant textbook Matter and Interactions, in particular the section that deals with how the surface charges in an electric circuit distribute themselves to generate ...
0
votes
0answers
33 views

Diode's volt-ampere characteristics

The Problem is that If the reverse saturation current is $10\ \text{nA}$ ($1\ \text{nA}=10^{-9}\ \text{A}$), Calculate the forward current while the forward voltage is $0.6\ \text{V}$. And explain ...