Questions tagged [electric-circuits]

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

Filter by
Sorted by
Tagged with
-2
votes
0answers
18 views

Why in a RC circuit is the resistance multiplied by the capacitance equal to the time constant (inverse of the exponential growth rate)

The first three sections of this question ("Background", "Terms", and "Description of a capacitor’s charge over time in a direct current RC circuit") builds up the ...
0
votes
1answer
22 views

Will a generator turn a lamp on in open circuit if the lamp is connected to the earth which is greedy for electrons?

Consider the following thought experiment. One end of a lamp is connected to one terminal of a power generator. The other end of the lamp is connected to the ground via a metal copper as follows. ...
0
votes
1answer
28 views

In a simple electric circuit with battery and lamp, how does the lamp light up?

I watched Veritasium's video on big misconceptions of electricity, i remember when we learn how does lamp light up in the circuit, our teacher said it is the kinetic energy of electrons transfer to ...
-1
votes
0answers
32 views

Derive a mathematical model for the passive electrical network shown in Figure [closed]

This system is a passive electric system that must utilize the mathematical model to solve
-1
votes
0answers
28 views

How fast does an electromagnetic field come into existence? [duplicate]

In this video by the YouTube Channel "Veritasium" it is explained, that electrical energy is in fact not travelling through the wires of a circuit (in the form of electron flow), but instead ...
4
votes
7answers
1k views

Why doesn't a parallel circuit violate conservation of energy?

Let's imagine a hypothetical circuit where there are a large number of wires placed in parallel to each other, hooked up to a simple power source. We know that voltage at each wire would be equal $V_{...
0
votes
1answer
21 views

Does crystalline silicon have a higher (~3.0 eV) band gap than amorphous Si (~1.75 eV)? Or lower (~1.12 eV)?

Some sites claim that crystalline silicon has a band gap of approximately $1$ to $1.2$ or so electron volts, and others say it is about $3$ to $3.4$ eV.... Amorphous silicon is usually described as ...
-1
votes
3answers
84 views

How does current get reduced in resistor?

How does the resistor reduce the current? I know that when there is no resistor in the circuit the current is higher than the current when there is a resistor. But, my question is: How the resistor ...
0
votes
2answers
39 views

Finding potential at a point in a circuit

$I_1=20/7 A$ , $I_2=2/7 A$ and $I_3=18/7 A$ In this circuit can we calculate the value of absolute electric potential (or simply potential) at specific points like B or E or A etc ?? My textbook ...
-1
votes
0answers
32 views

Electric field in circuits and potential drop

With reference to the above image: Here the battery produces a constant (will it be constant? pl. explain) electric field across the length of the wire, lets say its value is $\vec E$ . This field ...
0
votes
2answers
39 views

Electric field inside a wire and potential difference

Suppose I have a battery of $V$ volts and a circuit is made using it. This battery produces a constant electric field which moves the electrons thus establishing current. Now what will happen to the ...
1
vote
1answer
47 views

How long does a headphone last on a given battery? [closed]

Sennheiser HD 598 has 50Ω impedance. It has a 3.6mm cable, but I am planning to do a simple DIY project to replace the cable with a bluetooth receiver, a 3.7V 1000mAh battery (and a charging board). ...
-2
votes
0answers
27 views

Current in an resistor [duplicate]

Suppose I have a electric circuit as shown in image Let a resistor is connected to a battery. The current starts flowing through the resistor. Why is the current entering the resistor the same as the ...
0
votes
1answer
58 views

Electric field inside a wire

For a uniform (constant) electric field, we have the relation $E = - \Delta V/\Delta r$. Now, if the electric field provided by a battery is constant over a constant potential difference and if we ...
-2
votes
0answers
22 views

What will be the currents through $R$, $L$ and $C$ at $t=0$ + (The complete question's provided in the image attached below)? [closed]

Choose the suitable alternative(s) Elements R, L, C are connected in parallel and excited by a DC source of l Amp. If IR. iL and ic are the currents through R, L, and C respectively. then at t=O+ i) ...
0
votes
0answers
24 views

Why do we have to do work to remove iron nucleus from an inductor?

Why do we have to do work to remove iron nucleus from an inductor? Since the energy associated with the inductor is $E=\frac{Li^2}{2}$, and $L$ is proportional to relative magnetic permeability $\mu_r$...
-1
votes
1answer
39 views

How can current be constant and still result in resistors having a voltage drop?

My issue arises when thinking about the situation like this. Current is the amount of charge flowing through an area, and resistance is basically they difficulty in doing so. My issue results when ...
1
vote
2answers
51 views

Can I apply Kirchhoff's current law to two separate nodes which are connected only by an ideal wire? [closed]

Suppose there are 2 nodes A and B in the above circuit. If A has 2 incoming currents $I_1$, $I_2$, and B has 1 incoming currents $I_3$, $I_4$, is it correct to write the equation of whole nodes and ...
0
votes
2answers
48 views

Can electric current flow through other battery in circuit?

Can electric current which started from $80$ V battery flow through $360$ V battery in the attached circuit pic? I know current flows in wire and it starts from anode, but I don't know, whether it can ...
-2
votes
0answers
29 views

Resistance of a wire doesn't depend on which of the following? [closed]

I don't know the answer of this question everything answer look same so please answer this
3
votes
2answers
815 views

What potential difference or current would kill a person?

I was watching this YouTube lecture, and earlier in the vid he mentions 120 volts from a power outlet would kill you. So if human resistance is $300\ \Omega$, $0.4 \rm A$ should be enough to do the ...
0
votes
0answers
22 views

How do I make 500-1000 kV dc voltage? [closed]

I found some inverters that turn 9v into 1,000,000 volts ac, but I need something that turns 9v dc into 1,000,000 volts dc. Is there anything that makes 1,000 kV dc>
0
votes
1answer
37 views

Is electrical resistance analogous to friction?

In a circuit, an electric field is produced from a circuit element providing a voltage source. Electrons flow through the circuit undergoing collisions which provide a resistive force to the electrons ...
1
vote
1answer
53 views

Circuit problem [closed]

Hello, can someone please help me on this problem? Question: calculate the potentials at A and B. The solution says that they are both 12V "due to symmetry" but I have no idea what is the ...
0
votes
1answer
21 views

Temperature coefficient

If we raise the temperature of any conductor the atom, free electrons starts vibrating There kinetic energy increases If kinetic energy increase then , Current must be increase As current increase ...
1
vote
1answer
43 views

Does the resistance of a filament lamp change?

Recently in a work book there has been a question to explain with the aid of a circuit diagram the method a student could use to investigate how the resistance of a single lamp changes with potential ...
0
votes
2answers
29 views

I don't understand why for resistors in AC circuits the phase angle between voltage and current is zero

From the following graph I understand it is because they reach the voltage and the current reach their maximum values at the same time on the resistor, but I don't understand why this should be that ...
0
votes
1answer
40 views

Huge current flows when there is no resistance, consequently, the potential difference is 0 but no current flows if no cell is added to the circuit

If $R= 0$ , $V= 0$ and $I=$ $max$ (i.e. charges are flowing at a huge rate), but when there is no potential difference applied to a circuit, charges don't flow. That means huge current flows when ...
0
votes
4answers
37 views

Is potential difference required only to overcome resistance in a conductor?

In free space, a potential difference is required for the flow of a charge though there is no resistance. In a conductor, a potential difference is required only to overcome the resistance, am I right?...
-1
votes
2answers
35 views

Conversion of potential energy of charge into kinetic energy

Suppose I have a battery of voltage v which can flow $Q$ coulomb of charge through a metalic conductor When voltage is applied across this conductor the electrons inside it get accelerated and move ...
7
votes
9answers
2k views

Why is the current entering a conductor the same as the one exiting it?

Suppose I have a conductor connected to a battery. The current starts flowing through the conductor. Why is the current entering the conductor the same as the current leaving the conductor? Its ...
-1
votes
2answers
31 views

Current and voltage in series combination of resistors

In a series combination of resistors , current through each resistors is same but, how is it possible for current to be same if all the resistors have different resistance . the current has to apply ...
3
votes
2answers
331 views

How does energy flow in a circuit? (Veritasium vs. Science Asylum) [duplicate]

I have recently watched two YouTube videos on this subject, that you can see here (first by "Science Asylum" and the other by "Veritasium"). https://youtu.be/C7tQJ42nGno https://...
1
vote
1answer
151 views

On Poynting vector and electric circuits

Consider the following setup. The answer is $(3)$ - spoiler alert - and it's explained here, using Poynting vector. The thing is though How can the electromagnetic energy flux even reach the light ...
5
votes
4answers
273 views

Alternate explanation for energy flow in electricity as explained in this video

The question is about this video from a youtube channel called Veritasium. It is a popular physics/math youtube channel and topics discussed are usually fact checked and accurate. The gist of the ...
3
votes
1answer
345 views

Veritasium Electricity Follow-Ups: Insulators, Switch Location, larger gap

This question is similar to: Doesn't Veritasium's Recent Video About Circuits Violate The Speed Of Light? In what order would light bulbs in series light up when you close a long circuit?, ...
0
votes
0answers
16 views

Capacitors with plates of opposite polarity connected at some voltage

Halliday/Resnick/Krane Vol. 2 contains the following problem: "A variable, air-filled capacitor of the type used in tuning radios is shown. Alternate plates are connected together, one group ...
13
votes
3answers
969 views

Doesn't Veritasium's Recent Video About Circuits Violate The Speed Of Light?

A recent Veritasium video discusses the following circuit: ...
20
votes
4answers
4k views

Are the "bird sitting on a live wire" answers wrong?

Long ago, my high school teacher wrote the popular question on board, "Why doesn't a bird sitting on a live wire get electrocuted?" He gave us four options (I don't remember all of them) ...
1
vote
1answer
39 views

What would happen if we were to put a resistor at a junction?

I am currently studying electrical circuits in high school, and at some point I wondered what would happen if we were to create three (or more) connections on a component and put it at a junction. For ...
0
votes
2answers
30 views

Voltmeters / direct measurement of voltage in a circuit

I was wondering that many instruments that measure the ddp in a circuit works measuring instead current and then applying Ohm's law. When I looked for how Ohm made his initial measurements for voltage,...
0
votes
1answer
28 views

Asking for proof for total voltage is equal to the sum of the voltages of the resistors (connected at series pattern) [closed]

Recently I was taught that when a set of resistors are connected as a series pattern the total voltage of the resistors is equal to the sum of the voltages of each resistor. I know how to prove this ...
1
vote
1answer
35 views

Energy loss in a circuit during critical damping [closed]

I would like some intuitive explanation regarding impedance in an $RLC$ circuit. So far, my understanding has been limited to underdamping situations where both resistance and reactance are present. ...
1
vote
3answers
57 views

I have trouble understanding why two different capacitors should have the same amount of charge on each side of a circuit

There is a rhombus with four different capacitors. There's a voltage between the point $a$ and the point $b$, but there is no voltage between the point $c$ and the point $d$. Apparently, assuming that ...
1
vote
4answers
75 views

Why is current = 0 in open circuit?

This is an open circuit. Now , a chemical reaction happens in the cell which makes the current to flow in the wire. Then , the current has no other place to go , so it just gets grounded. It is ...
0
votes
0answers
32 views

Is effective EMF always greater or less than individual EMFs?

When we connect many Resistors with Resistance = $R_{i}$ in series, we get an equivalent resistor with resistance equal to $R_{eq}=R_{1}+R_{2}+R_{3}...$ This logically implies that the equivalent ...
-1
votes
1answer
23 views

What are the steps that give rise to this following resistance equation for a diffusive transport of electrons?

$ R = R_b (1 + \frac{\lambda}{L})$ Source - page 6 of this book: https://nanohub.org/courses/FON1/01a/asset/15698
-1
votes
0answers
22 views

Is the terminal voltage twice the EMF when the battery is being charged and short circuited?

So, I know V terminal= E- Ir during discharging of a battery. 'E' is the EMF, 'r' is internal resistance of the battery and 'I' is current. If the battery is short circuited, 'I' becomes = E/r because ...
0
votes
0answers
40 views

How does a superconducting qubit exists in the superposition of $|0\rangle$ and $|1\rangle$ states?

In the presentation of superconducting qubits, it is often said that a non-linear inductor is what allows the present of an anharmonic oscillator. This means that because the difference between the $|...
1
vote
0answers
34 views

When can we quantize the Hamiltonian for an LC circuit?

For a superconducting qubit, we start with an LC circuit and "quantize" it, mapping the variables analogously to the variables for the harmonic oscillator. In general, when are we allowed to ...

1
2 3 4 5
76