What is Circuit: Definition and 1000 Discussions

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. SSGD

    I Optimization of an Amplifer Circuit

    The gains of an OP-AMP are listed below: G_d = (R_1*R_4+R_2*R_3+2*R_2*R_4)/(2*R_1*(R_3+R_4)) G_s = (R_1*R_4-R_2*R_3)/(R_1*(R_3+R_4)) \frac {\partial G_d} {\partial R_1} = -R_2*(R_3+2*R_4)/(2*R_1^2*(R_3+R_4)) My questions is... Is there a mathematical perform the following: Differential gain...
  2. M

    Can somebody tell me the calaculations of this 2 transistor circuit?

    can somebody tell me this circuits calculations, how come 10mA please
  3. T

    For a damped RLC circuit, why must R be small?

    Homework Statement I'm reading the textbook section covering damped series RLC circuits (provided below). I'm wondering why the author stipulates "When R is small..." Homework Equations Given above. The Attempt at a Solution Given above. Any gentle and courteous comments are welcome!
  4. R

    Wires in an circuit, different materials, heat

    Homework Statement In an electric circuit, consisting of copper wires with cross section area of Sc=5mm2 and a temperature of t=25C, a lead fuse is added melting when the copper wire temperature increases by Δt=25C. Find the cross section area of the lead fuse wire Sl=x. specific heat...
  5. E

    Effect of Dielectric Material on Capacitor Voltages in a Circuit

    Homework Statement C1=C2=C3=C No internal resistance. We wait for a while and the put a dielectric material in C3. Then after waiting again we remove the voltage source and after that we take this material out. How will the voltages on the capacitor be affected? Homework Equations CV=Q The...
  6. E

    Combined resistance in this circuit

    Homework Statement What is the combined resistance when the switch is closed? Homework Equations IR=V The Attempt at a Solution I found that I1=5.2A and that I2=9.1A. The answers follow suit. Now I thought that calculating the combined resistance with 60/(I1+I2) would be correct, however the...
  7. billyray

    Engineering Equivalent Single Load for Complex Delta and Y Connected Loads

    Homework Statement a) the equivalent single Δ-connected load I have uploaded circuit Homework Equations none yet The Attempt at a Solution I am not sure if the question is asking me to find the resistance of both delta and y connected loads then work out them both in parallel. After I have...
  8. J

    Inductance of a double circuit line -- struggling with return the path

    So for inductance of transmission line book says formula H = 2 * 10 -7 Loge { [Ds]/[Dm] } I'm struggling to understand self and mutual geometric mean distance. Here is one solved example and for this they've drawn And they say that let a a' form one connection and let b b' form other...
  9. T

    How charges can flow in circuit wires at the same potential

    I have this simple circuit I know that if a consider the wire from the + of the battery until the + extreme of the resistor, in this portion the wire has the same potential. The same thing regarding the portion of the wire beetween the - of the battery until the - of the resistor. If this...
  10. Pushoam

    Engineering LCR circuit, calculating R when frequency width is given

    Homework Statement Homework EquationsThe Attempt at a Solution LCR circuit, calculating R when frequency width is given Applying Kirchoff Voltage Loop Law, ## V_A – V_B + V_B - V_C + V_C – V_A = 0 ## ...(2) ## V_A – V_B ## is potential drop across inductor. Since current is flowing...
  11. B

    Engineering Calculate the resistance in the circuit

    Homework Statement All resistors are ## R = 10 \Omega## Homework Equations Calculate the total Resistance The Attempt at a Solution all resistors are parallel, so $$ \dfrac{1}{R_{AB}} = \dfrac{1}{R} + \dfrac{1}{R} + \dfrac{1}{R} + \dfrac{1}{R} + \dfrac{1}{R} + \dfrac{1}{R} $$ ## R_{AB} =...
  12. F

    Current flowing from point A in a circuit to point B

    Homework Statement A current at point A of 2A flows through a resistor (3 ohms), a battery of 20V (negative terminal first), another resistor (1 ohm) and a battery of 6V (positive terminal first). What is the potential difference between A and B Homework EquationsThe Attempt at a Solution I...
  13. Aya Elsayed

    The circuit of the induction coil

    When we turn the circuit off . There will be an induced emf through the coil due to the changing magnetic field of the AC . Therefore V=-L . DI/Dt So when the current is zero then the emf has a maximum value . And what about the emf of the source itself ? It's equal to the induced emf? If It...
  14. J

    AC circuit Multiple choice question

    Homework Statement More than one options may be correct . Homework Equations Inductive reactance =ωL Capacitive reactance = 1/ωC The Attempt at a Solution On increasing the frequency , inductive reactance increases whereas capacitive reactance decreases . Thus , option a) is correct ...
  15. J

    Engineering What is the Time Constant for an RLC Circuit?

    Homework Statement Homework Equations I know for RL circuit T = L/R For RC circuit it is RC But how to go ahead for RLC circuit.The Attempt at a Solution I calculated for RL as 1/4 = 0.25 And RC as 1 Then I added both time constant and got 1.25 Book answer is 0.5. How to solve this? In...
  16. Y

    Why do I get different answers with different methods - Thevenin

    Homework Statement Determine the Thevenin equivalent of the following circuit: https://imgur.com/a/74UjA (Top image) Homework Equations - The Attempt at a Solution The last 3 images in the Imgur album are all different approaches. I can't figure out what the right one is, and why the other...
  17. E

    Finding the battery voltages in this circuit

    Homework Statement This circuit is given:[/B] What are the values of ε1 and ε3? Homework Equations IR=V The Attempt at a Solution I get the right answer for ε1 (3V). But I get that ε3=12V and not 15 (the answer in the textbook). First the charge from a to b is 3A. Then I simply use...
  18. H

    Can you help me find the current through the 15 Ohm resistor branch?

    Homework Statement Homework Equations I = VR Series = current the same, voltage different Parallel = current different, voltage the sameThe Attempt at a Solution Is the 1 ohm and 15 ohm parallel? I'm still learning to differentiate it. If yes, then R = 15/16 ohm Is the R series to 5ohm? If...
  19. billyray

    Help with Node Analysis Circuit Problem

    Homework Statement I have a circuit which I have a current through labelled I on circuit. I have -9.18 +j17.31. we agreed this was correct. I have a node analysis problem but cannot find the correct answer. I feel my method and my maths may be off but would like some advice if possible...
  20. D

    Circuit Model for a Rotary Contact?

    Hi Everybody, First post on the forum, this one's stumped me I'm afraid. I'm basically trying to model a rotary connection in an AC circuit, and I'm having a bit of trouble with it. Ideally I'd like a reasonable approximation with conventional circuit elements. Basically I've got a...
  21. Frankenstein19

    Engineering Short circuit confusion, when is the resistance 0

    Homework Statement [/B] I'm going exercises and I understand that if the circuit is short circuited that R=10 ohm is 0. (Trying to find Thevelin R in all of these btw) But then I ran across this one where when it's short circuited, isc is found using the current divider principle and it's...
  22. R

    Engineering Impulse Response of an RLC Circuit

    I bolded the portions I need help with. 1. Homework Statement A series circuit consists of a resistor with a resistance of 16 ohms, an inductor with inductance of 2 H, and a capacitor with a capacitance of 0.02 F. At time t = 0 there is no charge on the capacitor and no current in the circuit...
  23. H

    Find the current I in this electrical circuit

    Homework Statement Homework Equations V = I.R The Attempt at a Solution 6 ohm and 3 ohm are series = b Then b pararel to 9ohm = c = total resistance b = 9ohm c = 9/2 ohm I = V/R I = 9.6/c I = 2,13 A Can you help me? Is it right? My friend's answer is 0,8
  24. Z

    Magnitude of the transfer function

    Hi all, In one of my problems there is a question with a plot of the transfer function magnitude versus frequency. In the graph I notice that the magnitude of the transfer function is greater than 1. This is confusing as I thought that filters are not able to increase the magnitude of the output...
  25. yecko

    Engineering Parallel Circuits: Learn How to Connect 2k & 4k

    Homework Statement Homework Equations Parallel circuit The Attempt at a Solution How can we see 2k//4k (parallel)? There are 2*2k & 2*4k. thanks. (Though I can obtain the same answer by KVL)
  26. yuvalidan

    What is the Hamiltonian for an LC circuit?

    Homework Statement Hi i got a problem in lc circuit, I need to find the hamiltonian to this circuit , I think that I did well but I am not sure, the problem and my attempt in the following file. Homework EquationsThe Attempt at a Solution
  27. VSayantan

    Current through an Ammeter in an Electric Circuit

    Homework Statement [/B] It is required to find the current through the ammeter, marked A, in the above figure.Homework Equations ##V=iR##The Attempt at a Solution I've redrawn the circuit as follows - But don't know how to obtain the value ##i_3##
  28. C

    Finding Potential Difference Across AB in a Multi-Cell Circuit

    Homework Statement Find potential difference across AB Homework EquationsThe Attempt at a Solution I have posted a picture of my figure, I have 3-i1=v=2-i2=1-i3 and i1+i2+i3= io on solving I got 6-io=3v and then I found resistance equal to 1/3 ohm. So after solving I got v= 1 volt, but it's wrong
  29. C

    Potential difference in multi cell circuit

    Homework Statement Find potential difference between a and b in the figure Homework Equations Q=cv The Attempt at a Solution can anybody tell me how to apply the equation in this problem with more than one cell [/B]
  30. billyray

    Engineering Superposition calculation for a circuit

    Homework Statement I have tried to answer the superposition question in the included file. I have gone through the workings as the same as in my john bird electrical book. I believe I have done nothing wrong in my approach and should be getting the same answer as my thevenins answer. the...
  31. reddvoid

    Energy consumed in a digital circuit

    I have a digital circuit , to find the energy consumed by the circuit, I am monitoring the current drawn from the supply and integrating it to get the charge pumped into the circuit ... and the total charge*V supposed to give me total energy consumed by the circuit. But I am getting a small...
  32. J

    Source free RL Circuit derivation

    Hi, I'm struggling with source-free RL Circuit derivation. In the books in the right side diagram they've reversed polarity of inductor to get equation: V(r) = - V(L) But why? I checked google and everywhere they had put inductor with positive sign upwards. Here is what I think-- In left...
  33. R

    Can't find correct expression for discharging RL circuit

    Homework Statement After a switch is left for a for many time constants, it is switched to b. find an expression for the total charge that passes through the resistor in one time constant Homework Equations dq/dt = I(t) I(t) = (ε/R)(e^(-tR/l)) The Attempt at a Solution so dq = I(t) dt I know...
  34. Drakkith

    Engineering Finding Current in a Parallel RLC Circuit

    Homework Statement Find io for t≥0. Express your answer in terms of t, where t is in milliseconds. There is no energy stored in the circuit in (Figure 1) when the switch is closed at t = 0. Homework Equations ##x(t)=x_f+[B_1cos(ω_dt)+B_2sin(ω_dt)]e^{-αt}## The Attempt at a Solution Let...
  35. W

    What is the role of cosφ in calculating power in LRC series circuits?

    Homework Statement With just about any problem asking for "rate at which source is delivering electrical energy to the circuit" or "find the power of the circuit" in a LRC circuit, I get that you have to calculate for the average power. But the multiple equations confuse me - sometimes in...
  36. G

    What about the electric field in a circuit with resistors?

    Hi. I am having some trouble understanding what is the voltage drop in a system with resistors in series. If there is a difference of electric potential between two points in space, since electric potential is electric potential energy per charge, there is a difference in the electric...
  37. Drakkith

    Engineering Current Through a Capacitor in a RC Circuit

    Homework Statement Find ##i(0^+) ## and ##i(t), t≥0^+## Homework EquationsThe Attempt at a Solution [/B] I'm having trouble finding the current through this capacitor. I tried using a KVL loop for ##t=0^+##, but I'm doing it incorrectly or something. Earlier in the problem I found...
  38. C

    Engineering Laplace Transform on RC circuit

    Homework Statement Homework EquationsThe Attempt at a Solution I'm kind of lost now, how do I go about getting this into the right form for partial fraction exapnsion. And also what do I do with the V(0'). There was no information given about it.
  39. G

    Getting negative current on Zener Voltage Reg Circuit

    i've built a bridge rectifier with a Zener Voltage regulator. 12V peak secondary 3300uF Capacitor 1k ohm load 1k ohm series resistor for the zener and a 1n4728A Zener diode. i'm getting a 2.8V steady voltage, but when i measured the current going through the load with my DMM it's measuring...
  40. P

    Unsolved Circuit Question: Ammeter Reading and Potential Difference

    Homework Statement So here is a circuit question that I couldn't solve Homework Equations V=IR The Attempt at a Solution So I assumed that since the ammeter gives no reading it should lead to no potential difference in between those two points, then I'm completely stuck. Please help, the...
  41. T

    Retired Railroader Explains Easiest AC Circuit Theory

    I am retired from a major railroad co. where I worked on electronic weighing equipment. I have an associate of applied science degree from a local university. I have a basic understanding of dc and ac electricity but the explanation I recently read on this forum was the easiest to understand...
  42. Drakkith

    Engineering Energy Dissipated in an RL Circuit

    Homework Statement In the circuit shown in (Figure 1) , the switch makes contact with position b just before breaking contact with position a. As already mentioned, this is known as a make-before-break switch and is designed so that the switch does not interrupt the current in an inductive...
  43. J

    Inserting a conductor in a parallel-plate capacitor

    Consider a parallel plate capacitor formed by two plates of length ##L## and width ##d##, separated by a distance ##e##. There is a vacuum in between the plates. Let's note the capacitance of this arrangement ##C_0##. I insert a conducting plate of length ##l=L/2##, with ##D##, and thickness...
  44. Sainvictus

    Examine the following circuit. Now complete the table.

    Homework Statement Homework EquationsThe Attempt at a Solution
  45. G

    How do you find the current going through a weird circuit?

    Homework Statement Homework Equations at point C: i2 - i3 - i4 i2 = i3 + i4[/B] The Attempt at a Solution I labeled all the currents going through each resistor in the picture[/B] for loop ABC: 2000i1 = 3000i2 + 4000i3 for loop BDC: 3000i5 = 2000i4 + 4000i3 at point C: i2 - i3 - i4 i2...
  46. M

    Question about circuits with transistors (current, voltage)

    Homework Statement 1. In Figure A-1 of Experiment 18, assume that Vdc = 8Volts, R1 = 1kOhms, R3 = 7kOhms and there is no R2 resistor. Determine the current in R1 when the transistor is fully on and carrying current. Express your answer in mA. 2. In the circuit of Figure A-1, Experiment 18...
  47. B

    LCR Circuit with Driving Force

    Homework Statement a. express the equation of motion b derive impedance at the resonant frequency (ω=ωo) c derive impedance at very high frequencies (ω>>ωo and ω>>R/L) Homework Equations Vo=ψ+(R/L)ψ+(1/LC)ψ Z=(1/iω)K(ω) K=1/((s-mω2)+ibω) The Attempt at a Solution Part a was simple, that was...
  48. mkematt96

    Engineering Help finding error in my Circuit Analysis

    Homework Statement Homework EquationsThe Attempt at a Solution My values for i1,i2,and i3 were: -.005179,-.002857 and .004857. When I ran the same circuit through LT Spice the values they gave me were .00059081,.000809628, and .00119037. Where did I make my error? * as a side not I...
  49. anorlunda

    Insights The What and Why of Circuit Analysis Assumptions - Comments

    Greg Bernhardt submitted a new PF Insights post The What and Why of Circuit Analysis Assumptions Continue reading the Original PF Insights Post.
  50. Jayalk97

    Engineering Underdamped Parallel RLC Circuit

    Hey guys, so I'm having trouble with this circuit analysis question. I need to find voltage across the capacitor as a function of time. I nearly finished analyzing but I'm having trouble solving for the initial value constants in the voltage equation. So first I used KCL to create the equation...
Back
Top