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

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3answers
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EMF or terminal voltage?

I have a doubt that is: What does this statement mean: "a 6 V battery". Does this mean that the EMF of the battery is 6 V or the terminal voltage of the battery is 6 V? If the battery has internal ...
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2answers
43 views

Contradiction about cross-sectional area being inversely proportional to resistance

Let us consider a fixed voltage. $ I = nAve $ is the relation between current, number of free electrons in unit volume $(n)$, cross-sectional area $A$ and electron drift velocity $v$. ($e$ is the ...
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2answers
54 views

Why don't capacitor charging graphs look like other exponential growth graphs?

Sorry if this question is stupid, but I can't find any answers for this online. Physics websites show that capacitors charge and discharge exponentially. The discharging graphs of charge against time ...
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2answers
4k views

Calculating the energy supplied by a battery

If you wanted to calculate the energy supplied by a battery in time $t$ you would use $E=VIt$ where $I$ is the current through the battery. If the internal resistance is $r$ we could also use $E=\frac{...
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1answer
45 views

Basic circuit problem [closed]

The voltmeter has infinite resistance. What are the readings on the voltmeter when the switch is open and when it is closed? I thought that the reading on the voltmeter would be E/2 regardless of ...
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4answers
1k views

Difference between $I^2R$ and $V^2/R$ and $VI$ for measuring power $P$

We use $I^2R$ or $V^2/R$ or $VI$ for measuring power $P$. Are all of these applicable for all circuits? I have seen in some circuit $V^2/R$ is not equal to $I^2R$. Why is that?
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0answers
35 views

RL vs RLC circuit magnetic field

If I want to create an alternating magnetic field using an inductor, what difference would it make to use a series RL or a series RLC circuit ? How will the presence of a capacitor affect the magnetic ...
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4answers
41 views

Light bulbs in Series

In physics we were learning about how in series the current is the same through each resistor. So that the lightbulbs will all have the same brightness but dimmer than if there was just one bulb on ...
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1answer
66 views

Magnetic field of a solenoid vs magnetic circuit

The magnetic field in the middle of a solenoid is : $$B = \frac{\mu_0 N I}{L}$$ where L is the length of the solenoid The magnetic field in the air gap of a magnetic circuit with constant cross ...
4
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2answers
191 views

Will the two capacitors be charged in this circuit?

Is such a circuit possible to exist with the two capacitors charging? Because if we considered the outer loop using Kirchhoff's law we get: ℰ = q1/C1 + q2/C2 But since the two capacitors are ...
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1answer
30 views

Why is the electric field homogenous inside a circuit?

In a circuit between to poles of a battery, there is an electric field accelerating the charges in the wire towards lower potencial (but due to resistivity they only travel at drift velocity). Is ...
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1answer
20 views

How is a change in capacitance detected in a touch-screen?

So the screen has lines of conductors horizontally and vertically, seperated by a dielectric, and thus forming a grid of capacitators where the ones in one "row" are in parallell on the one side, and ...
3
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1answer
109 views

Do light dimmers save energy and lower your electric bill? [closed]

Or do they just capture the incoming energy and turn it into heat at the unit and save you nothing?
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8answers
2k views

Why is capacitance defined as charge divided by voltage?

I understand that capacitance is the ability of a body to store an electrical charge and the formula is $C=\frac{Q}{V}$. What I don't understand, however, is why it is defined as coulomb per volt. Of ...
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2answers
41 views

Steady state RLC circuit analysis

In an RLC series circuit let applied EMF be given $V=V_0\sin\omega t$, $$Z=Z_C+Z_R+Z_L=R+i\left(\frac{1}{\omega C}-\omega L\right)$$ $$|Z|=\sqrt{R^2+\left(\frac{1}{\omega C}-\omega L\right)^2}$$ Then ...
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1answer
49 views

Question for power and Ohm's law [closed]

I have two questions specifically. Can the usage of Ohm's law be utilized to predict current, voltage in circuits such as parallel, complex and series? How would I explain this? How does the power ...
0
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1answer
30 views

Capacitor and inductive coil in AC circuit

Does increase in $L$ of inductive coil with variable no. of turns or $C$ of capacitor with changeable capacitance increase frequency of the circuit?
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1answer
29 views

If a battery is open on one end but connected on the other, does it raise the potential on the connected end?

If a battery has one end open and other end connected to a circuit will the battery increase the potential at the point of connection?
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1answer
44 views

What is the work done by battery and what does work done on battery mean?

Suppose we have a charged capacitor connected to a battery. Now we push the plates of the capacitor away from each other decreasing capacitance and hence energy stored in the capacitor decreases. Now ...
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5answers
104 views

Brightness of 2 Lightbulbs hooked up to Capacitor [closed]

The figure shows a circuit consisting of a battery, a switch, two identical lightbulbs, and a capacitor that is initially uncharged. a. Immediately after the switch is closed, are either or both ...
3
votes
2answers
81 views

Why do some people support more electricity than others?

There is a game where people hold by their hands and two of them touch the electrodes of a shock box, then an electric current flows through them. I understand that since they are all making a single ...
0
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1answer
616 views

Is this a series or parallel connection? [closed]

I am confused how the capacitors in this circuit are connected. $C_4$, $C_6$ and $C_5$, $C_3$ appear to be parallel, but both $C_4$ and $C_6$ seem to be in series with $C_1$ as do $C_5$ and $C_3$. Am ...
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2answers
38 views

Why do people say that 'power flows' into or out of a component in an electric circuit?

Currently, I am learning about electric circuits, and how to apply the basic concepts of physics, like work and energy. But I keep running into the same phrase--on Wikipedia, my textbooks, everywhere--...
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2answers
52 views

Why is a circuit of linear elements itself linear?

A resistor's voltage is proportional to it's current. V=iR. And a source maintains a constant voltage or current. So these are linear, time independent relations. If I put combinations of them in a ...
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2answers
31 views

Phase difference in currents in parallel RC circuit

shouldn't the phase difference be 0. The potential difference across any branch at any instant should be V.so what's wrong ?btw correct answer is (C)
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1answer
21 views

On a AC to DC adapter there are +12v wire with 24A and -12v have 0.5A. How many amp this adapter will provide in total? [closed]

I have a PSU of a pc which is 500w. I want to charge a 12v 100ah battery which need 20 amp of current. Is this psu can provide current that I have wanted? Main question is On a AC to DC adapter (PSU)...
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1answer
43 views

Spherical 'capacitor' with only one charged plate

A question I came across asks about two concentric spherical conductors where only the inner sheet is charged. The question first asks to find the capacitance of such an arrangement. The first part ...
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0answers
23 views

Solving traveling wave using the shooting method

The spatially-dependent Hodgkin-Huxley equation for a cylindrical dendrite or unmyelinated axon: where $\frac{a}{2\rho}\frac{\partial^2V}{\partial x^2}$ is a diffusion term $a$ is the fiber radius, ...
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votes
3answers
89 views

Why is $\text{R}$ resistance in $\text{V=IR}$? [closed]

Today I studied about Ohm's law which states- The current through a conductor between two points is directly proportional to the voltage across the two points.By introducing constant of ...
0
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2answers
470 views

Capacitors in a series circuit with dielectric

When a dielectric slab is inserted between the plates of one of the two identical capacitors in Fig. 25-23, do the following properties of that capacitor increase, decrease, or remain the same: (a) ...
0
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5answers
642 views

Why is there a potential difference?

The question then asks for the potential difference between $X$ and $Y$, which is claimed to be $3.6\text{ volts}%$. Why would there be a potential difference in this case? If I connect a lightbulb ...
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1answer
37 views

Charging of a battery

A battery has an Emf 6 Volts. It is completely discharged. It is charged by maintaining a potential difference of 9 Volts across it. If the internal resistance of the discharged battery is 10 ohms, ...
0
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1answer
21 views

Does the thermal expansion of a conductor contribute to its change in resistance when it is heated?

We know that the resistance of a conductor varies with a change in temperature and we are taught that this change occurs due to the change in resistivity of the material but does the thermal expansion ...
0
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2answers
64 views

Use of rheostat in a potentiometer practical?

in potentiometer practical why a rheostat is used in series to potentiometer wire? as we move the jokey the primary circuit current will also change. so is it to flow same amount of current by change ...
1
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2answers
35 views

What is the player's role in the functioning of a theremin?

I recently see a video on how the theremin works, and wasn't satisfied with the answer. I watched around, but they all seem to give the same explanation. A diagram as below is given, and it is ...
0
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5answers
72 views

Why current in series circuit is the same?

I have read in the internet that the charges do not have any other path to go and they must go through the same in a series circuit,hence the current is same. It was quite convincing but what ...
0
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1answer
25 views

Capacitor in AC circuit

Can someone explain to me the process of discharging of a capacitor when the EMF of AC source is decreasing? And where do charges go? I mean if there's a weak battery, it will be charged but what ...
0
votes
2answers
36 views

If the potential drops across a resistor (=$V_d$) then shouldn't the potential difference be the $\epsilon-V_d$?

Consider the following circuit: Suppose a current $I$ travels in both the branches, then as the current $I$ passes through the $60$ ohm resistor, there will be a drop in the potential of $60I$. ...
1
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2answers
528 views

Potential Difference of a wire?

Imagine a circuit with only a 12 Volts battery and a wire connecting the ends of the battery. Point A and point B lies on the wire. What is then the potential difference between point A and B if the ...
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3answers
6k views

Resistor cube problem solving method

I was solving problems from Irodov when I came across the method called point of symmetry method. I cant find this method anywhere. So what is this method? Here is the link to the problem solution ...
1
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2answers
4k views

Why do voltmeters and ammeters have high and low resistance respectively?

I understand why voltmeters are connected in parallel and ammeters are connected in series, but why is it that to measure voltage, you must have high resistance, and to measure current, you must have ...
2
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1answer
38 views

Inductor potential difference direction

If you have increasing current going down an inductor, the inductor will produce a potential difference to produce a counter current in the opposite direction, or up. The lower potential is then on ...
1
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1answer
44 views

Kirchhoff's laws in phasor domain

While analysing AC circuits, we write voltage, current etc all with complex numbers namely "phasors". While studying the same, I wondered if Kirchhoff's laws held good with current and voltage in ...
3
votes
2answers
4k views

Why does voltage change in series circuit but not in parallel circuit?

Voltage divides after every resistor in series but not when placed in parallel. Please explain this with using very less or no mathematical equations. I have tried searching for an answer online but ...
1
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0answers
56 views

Finding Inductance in an AC RLC Circuit?

In the laboratory you find an inductor of unknown inductance $L$ and unknown internal resistance $R$. Using a dc ohmmeter, an ac voltmeter of high impedance, a 1 microfarad capacitor, and a 1000 Hz ...
-1
votes
1answer
57 views

What happens in the RC circuit when being charged?

Say I have this RC circuit and at the start, the switch is off (current going from left to right and the starting point is just above the battery). I understand that then the capacitor acts just like ...
-1
votes
1answer
234 views

Measured voltage on coil

I have a simple circuit of coil with inductance L $$u_c(t)= -L\frac{di}{dt}$$ and AC source with output voltage $u_s$ What is actually measured by the voltmeter ($u_c$, $u_s$ or $u_s - u_c$)? If ...
1
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4answers
230 views

Optimal method for solving circuit

This problem seems quite simple, and I can easily find a way to solve it but the possibility of error in my method is extremely high. This is just a sub-task of a bigger task but this is the only part ...
1
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0answers
19 views

With the help of a given charge is it possible to obtain a charge many times greater in magnitude

Consider a spherically conducting sphere. If a charge(say positive) is placed near the sphere, then it will lead to separation of charges inside the sphere.My question is, can we create charges more ...