Circuit Definition and 1000 Threads

A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit. Its basic function is to interrupt current flow after a fault is detected. Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation.
Circuit breakers are made in varying sizes, from small devices that protect low-current circuits or individual household appliance, up to large switchgear designed to protect high voltage circuits feeding an entire city. The generic function of a circuit breaker, or fuse, as an automatic means of removing power from a faulty system is often abbreviated as OCPD (Over Current Protection Device).

View More On Wikipedia.org
Recent contents Top users
  1. Xiao Xiao

    Engineering Finding V and I in a simple circuit

    So I know I have to use kirchhoff's Voltage Law so when I apply it's: -12+4i+2Vo-4-Vo=0 and Vo=6i so --> -16+4i+2(6i)-(6i)=0 but apparently that's wrong and Vo should be =-6i and so when I substitute it in the equation it should be -16+4i+2(-6i)-(-6i)=0 and I don't understand why.
  2. X

    Engineering How to Determine Voltage and Current in an RLC Circuit?

    Hi i want to know just how to approach this question. i know the omega=100 then should i find XL and XC? and then find the voltage in points c and d? also how do i find the current that enters point c? thanks a lot.
  3. cianfa72

    Exploring Quadripole Interconnected with External Circuit

    Hello, I'm struggling with the conditions under which makes sense employ a two-port 'external' representation of a quadripole (four-terminal electrical network) when interconnected to an external circuit (to take it simple assume a linear + permanent electrical network). Starting from circuit...
  4. J

    B RC Low Pass Circuit Sine Wave Response

    Hey Everyone, I am trying to gain a level of fundamental understanding of an RC circuit sine wave response through the mathematics and was wondering if someone could help me work it out. Fundamentally a sine wave is represented by the equation y=-ky'' . When a sine wave is used as the input...
  5. Pouyan

    Which lamp is dimmed in the circuit?

    The true answer is B. But I don't understand why! I know: Kirchhoff's circuit laws : ∑In=0 If we assume that a current that goes from plus to minus, before it passes through lamp B, I know that according to Kirchhof's laws, part of the current will pass through the bottom path where there is...
  6. Osnel Jr

    What factors affect the induced voltage in an induction circuit?

    I'm thinking it would stay the same. Any answers?
  7. Vossi

    Verifying a circuit design with voltage regulators

    Need help verifying if this circuit design and use of elements is correct. The goal here is to run a 3v motor, hence I need to make the use of voltage regulators for a constant 3v energy to transfer.
  8. Wrichik Basu

    How do you calculate the series resistance for this Triac control circuit?

    Disclaimer: Some of you might easily recognize that the components and circuit I am talking about are related to one of my projects, on which I had posted some months ago. Actually, the circuit is the same as the one in my project, but the one I am posting in this thread actually uses high...
  9. PRITAM the cat of Ne

    Engineering Op-Amp circuit output analysis trouble

    THE ANSWER IS GIVEN: 6V, but according to me as the positive terminal is grounded the negative terminal will be virtually grounded (0V), from ohm's law (applying to the two series resistance) it is expected that Vo is 0V! I don't know where I am getting wrong!
  10. qh4305

    Exploring the Zero Energy of a Circuit in a Magnetic Field

    Why is the energy of a circuit placed in a magnetic field at infinity zero?
  11. Xiao Xiao

    Engineering Electric Circuit Analysis of this First Order R-L Circuit

  12. hugo_faurand

    Amplifier for piezoelectric sensor, OP Amp circuit

    Hello everyone ! I'm working with a piezoelectric cell and I need to retrieve the variation of the charge of the cell as a voltage signal. I found this circuit (a charge amplifier) with an OP Amp ( here the piezo cell is represented as the current source with the capacitor and the resistor on...
  13. Andrei0408

    How do you calculate the impedance of the primary circuit?

    I'm not sure if it helps for what I'm looking, but I've calculated the mutual inductance, M, using the equation: M=U2/(ω*I1) = 106.3μH. I don't need the numerical value in particular, I just want to find a way to deduce the formula in order to calculate Z1. Thank you!
  14. T

    How Does Project 122 Snap Circuit AM Transmitter Work?

    Hi, guys! Could anyone provide an explanation about how the following AM transmitter works? It is similar to the AM transmitter for project 122 of the Snap Circuit kit by Elenco. Does it work as a switching modulator?
  15. E

    A query about this electrical circuit symbol

  16. Istiak

    Is My Delta to Wye Conversion Calculation Correct?

    I was following these [steps](https://www.allaboutcircuits.com/textbook/direct-current/chpt-10/delta-y-and-y-conversions/). I was calculating resistance for left side circuit. $$R_1=\frac{2 × 2}{2+2+4}=0.5\Omega$$ $$R_2=\frac{2 × 4}{2+2+4}=1\Omega$$ $$R_3=\frac{2 × 4}{2+2+4}=1\Omega$$ Then...
  17. Xiao Xiao

    Engineering Finding Vc for two circuits, Electric Circuit Analysis question

  18. B

    Induced EMF in a small square loop of wire at center of an AC Circuit

    I used the voltage of the power supply and resistance to solve for the current in the larger circuit (20V/5ohms=4 amps). I am not sure if the equation listed above is the correct one I should be using, but I tried it using the following numbers. For omega, I used 2*pi*frequency. N should...
  19. Z

    Don't know how to make an ultrasonic sensor circuit....

    Hello everyone, I am studying abroad and I am working on a speedometer project. I am preparing to use an ultrasonic transmitter and receiver to make an ultrasonic sensor circuit, and then connect it with the single-chip microcomputer msp430 to realize the functions of speed measurement and...
  20. Anubhav

    Oscillations in an LC circuit (Question from Irodov)

    https://www.physicsforums.com/attachments/282131
  21. brainbaby

    LT spice result analysis, Capacitance Multiplier vs RC filter circuit

    Hi friends, I have simulated two circuits, one is an RC filter and other is a Capacitance multiplier. My aim of experiment is to validate a decrease in Iout (load current) of CM circuit as compared to load current in RC filter circuit. Theoretically, Iout (CM circuit) < Iout (RC filter) Vp-p...
  22. Tim86

    DC current through a resistor circuit

    Summary:: Current through a certain resistor in a mixed dc circuit. Hi, Sorry if this is the wrong forum. I'm trying to work out the current through R1.The answer I need is 2 Amp, which I have confirmed with a simulation software. I have calculated the source current as 8A, the current past...
  23. J

    Calculate the impedance in this RC circuit

    So Z = sqrt[ R^2 + (1/wc )^2] and V=Ecos(wt) so I= Ecos(wt) / sqrt[ R^2 + (1/jwc )^2] but how do I use this to find the amplitude and phase of the current?
  24. R

    Circuit Analysis Theorem For the Number of Independent Equations

    I attached a screenshot of the book (sorry no pdf available for this book). Right above the somewhat central line they give the theorem that if there are m currents and n nodes, then there will be n - 1 independent equations from the current law and m - n - 1 from the voltage law. I count 4...
  25. M

    I Checking for negative feedback in a circuit

    This is the circuit in question. During lecture, when checking whether this was negative feedback, my instructor said that if the v_out increases, then v- increases as well, which would lead to the next v_out decreasing because v_out = A(v+ - v-). I get how if v- increases the next v_out would...
  26. M

    Some questions about capacitor discharging

    why does the voltage of the capacitor eventually go to 0 when discharging the capacitor? I heard that's because "current starts flowing when discharging", but how exactly does that lead to V going down? I know that I = C * dV/dt, but that doesn't seem to help me understand why V goes down (which...
  27. Xiao Xiao

    Electric Circuit Analysis, Nodal Analysis and finding Voltage.

    Summary:: The image shows two circuits, in the first one, using Nodal Analysis we find that V1=4.8V, but in the second circuit V1=10 because using KCL - 10+V1=0. I understand what happened in the first circuit, but I don't understand what happened in the second one, they look the same to me...
  28. Xiao Xiao

    Engineering Help in Electric Circuit Analysis -- One current source and a resistor network

    o9
  29. Z

    PWM signal generating circuit based on LM393

    This is a PWM signal generating circuit based on LM393. When I was running this LM393 circuit, I found that this circuit only consumes about 10 milliwatts of power at a voltage of 5V. Not only that, this circuit can work normally at 3.3V, 12V and 18V. But later I found that this circuit...
  30. C

    Current flow in a semiconductor circuit

    N/A
  31. Xiao Xiao

    Help finding Thevenim Equivalent - Circuit Analysis

    Summary:: So I found Vth=1.19 using Nodal analysis and I'm not sure if that's right, I'm trying to find Rth now but I'm confused as to what to do, any tip that tells me at least from where to start is appreciated. Edit: so I did 12||60 so Rth=10 ohm, is that correct? Is Vth correct too?
  32. Frigus

    Equal Peak Voltages in a Circuit: Is It Always True?

    In highlighted statement they are saying that vector sum of peak voltages of all components in circuit is equal to peak voltage of battery,I think they are saying this due to the fact that vertical components of both b and c diagrams are equal but what if their horizontal components are not equal?
  33. wcjy

    Circuits - Transfer function of this LRC circuit

    Got B = 9. My school doesn't provide answers, hence could someone double check if my answers is right? Thanks!
  34. hquang001

    Which Formula Should I Use for Calculating Power in an AC Circuit?

    Should i use P = V.I or P = Vrms.Irms.cosφ ?
  35. icesalmon

    Engineering What is the output for the following logic circuit?

    I obtained the following result: ([(A xor B) xor 0]* AC)' ([(A'B + AB') xor (0)]*AC)' [([A'B + AB']*(0)' + 0)*AC)]' [(A'B + AB')*(1)*(AC)]' [A'ABC + AB'AC]' [AB'C]' A'+B+C' the solution to this problem is getting a different answer, I don't know why this solution isn't inverting the output AB'C
  36. M

    Question about re-drawing circuit

    Hi, I was attempting this problem where the aim is to find the output current as a function of the voltage difference ## P_{in} - P_{out} ##. I just have two quick questions about this circuit: 1. If the 'reference voltage' (which I assume is how the ground voltage is referred to) is the same...
  37. S

    Engineering Can a voltage test source help solve for Rth in a complex Thevenin's circuit?

    So I've been absolutely stumped on this one. I've tried about a million different things but none of them have seemed right. A combination of the odd layout of the circuit, and a combined voltage/current source are making things really complicated for me. I'm somewhat sure the RTh is 15kΩ due to...
  38. patric44

    Is it illegal to reproduce someone circuit schematic in your paper ?

    hi guys i am trying to write a paper based on someone previous paper in which he discussed a simple electric circuit on some topic , my question is : is it illegal for me to reproduce the circuit schematic using multisim or something and properly cite them in my paper ? or i need their...
  39. L

    Transformers in a circuit, interpreting the label

    Hi hi, I was trying to use a transformer, that typical transformer that we have in house for a project, but then I notice something, well all this can be just a misunderstand from me. Actually a transformer have a voltage and a current, at least that is what it says the labels, "18V and 3A" for...
  40. wcjy

    Is My Approach to Solving a Source-Free RLC Series Circuit Correct?

    Hello, this is my working. My professor did not give any answer key, and thus can I check if I approach the question correctly, and also check if my answer is correct at the same time. for t < 0, V(0-) = V(0+) = 60V I(0) = 60 / 50 = 1.2A When t > 0, $$α = \frac{R}{2L}$$ $$α =...
  41. wcjy

    RLC Circuit Analysis -- Two sources and two switches

    Hello, this is my working. My professor did not give any answer key, and thus can I check if I approach the question correctly, and also check if my answer is correct at the same time. When t < 0, capacitor acts as open circuit, $$V(0-) = V(0+) = 9V$$ When t = infinity, $$V( ∞) = 5V$$ (because...
  42. M

    Engineering Circuit theory: capacitor energy storage and discharging/charging times?

    This is not my homework. I took it upon myself to answer a textbook question for mental stimulation. I wanted to know if someone can verify if these were the correct values that needed to be solved for, process, and final answer, and if not, what needed to be considered. For the initial...
  43. greg_rack

    Current flowing through a resistor in an RRL DC circuit

    DISCLAIMER: don't answer in terms of integrals, I haven't covered those yet :) Hi guys, I'm having a few troubles understanding RRL circuits, and have a few questions for you. A "normal" RL circuit will have a current growing inversely exponentially, starting from 0 and going to ##V/R## as...
  44. S

    Question about potential and current in potentiometer circuit

    Let say S is the balanced point so current flowing through galvanometer is zero. This is because the potential difference across PS is the same as potential difference across solar cell so no potential difference means no current flowing. My questions: 1) If I want to compare the potential at a...
  45. H

    Impedeance of parallel RLC circuit

    the impedance of the parallel RLC circuit is shown as attached. The equation above is the impedeance of RLC circuit in series, how can I convert that in parallel? Thanks.
  46. H

    What is the power factor in a series circuit?

    I calculated in the following and got the correct answer. However, I wonder whether this way is correct or not. Thanks! PR / Pavg = Irms^2 * R / Irms^2*Z = 15 /33.36 = 0.45
  47. H

    Understanding the Current Division Rule: A Circuit Diagram Guide

    Here's the diagram of the circuit: And here's the solution I found on a site on Google: I tried to follow through the solution given, but can't understand how it is applying current division rule to find current in QA and QB, and subtracting current values to find the current in AB is still...
  48. D

    Calculating the resistance in a compensating circuit for a thermocouple

    Homework Statement:: A K-type thermocouple is connected as shown to sense temperature. The temperature zone is at 25°C. The RTD has a resistance of 100 at 0°C and a TCR coefficient of 0.00385. A 5V power supply drives the circuit. Calculate R2 for proper compensation. What is the emf produced...
  49. wcjy

    Circuit problem with two sources and three resistors (Nodal Analysis)

    Ans: 0.123A Tried mesh analysis and got it but didnt for nodal analysis
  50. F

    Troubleshooting Neutral Cables in Electrical Circuits

    Last weekend I was in my friend house to change an outlet from 127V to 220V. This means changing the neutral terminal from the bar inside the electrical board (dont know if that's the right rem in english) into a phase. However, I couldn't identify which neutral cable was from the circuit I...
Back
Top