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).

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  1. Felipe Lincoln

    Verifying Kirchoff's law in an AC RLC circuit

    Homework Statement I have the following RLC circuit with an sinusoidal voltage generator and I want to verify the Kirchoff's first law with an oscilloscope. To measure the peak voltage in each of the components I just permute the positions between the component and the resistor. The question...
  2. F

    Engineering Unknown resistor in a series-parallel circuit

    Hey guys, I have tried and tried to find a start to this problem with no success. My book may have the answer but unfortunately I must be not realizing it. So hopefully I just need a different perspective. Typically I would find the equivalent resistance of the circuit and then begin to...
  3. K

    Basic Circuit Theory by Charles Desoer

    Hello, I am currently taking a circuits class and I was looking for the solutions manual for the book Basic Circuit Theory by Charles Desoer. I haven't been able to find it anywhere but I really want it to practice more of the problems. I am able to do some but I never know if they are right or...
  4. mjtsquared

    I On the stability of an LTI circuit

    An LTI circuit such as one composed of resistors, capacitors, and inductors, in general is a stable LTI system, i.e. its impulse response is one that decays over time. I have no problem with that, as it speaks for itself through laws of energy conservation, but I want to see this from a...
  5. kstorm19

    Solving a circuit using both the mesh and node analysis

    Homework Statement The problem asks to solve for i1, i2, and i3 using the mesh method in the following circuit: I will also include the link, because I noticed I am having trouble attaching the image to the post: https://imgur.com/a/bBvuLXM I would also like to confirm the answer by solving...
  6. F

    Engineering Why Does the Output Y Differ in the Moore Circuit Timing Diagram?

    Homework Statement Fig. 3-3 is a Moore type sequential circuit composed of a positive edge triggered D flip-flop and a combinational circuit. X is input, Y is an output, and CLK is a clock. Please show how Qo, Q1, and Y change when input X is given to this circuit at the timing diagram shown...
  7. Felipe Lincoln

    Analysing a double capacitor circuit with no battery

    Problem: At the instant ##t=0## the capacitor C1 has a charge ##Q_0>0## and the capacitor C2 has no charge. (I forgot to draw the switch to close and open the circuit), so the switch is closed and the current start flowing. Let the circuit goes to ##t\to\infty##. a) What's the energy stored in...
  8. Ruskointhehizzy

    Need help finding current on RC circuit

    Homework Statement In the circuit shown in the figure each capacitor initially has a charge of magnitude 3.60nC on its plates. After the switch S is closed, what will be the current in the circuit at the instant that the capacitors have lost 80.0% of their initial stored energy? the shown 3...
  9. scoutdjp2012

    Conducting rod creates a complete circuit

    Homework Statement A conducting rod makes contact with rails to complete a circuit. If the rails are 50 cm apart ina uniform magnetic field B = 0.38 [T] directed out of the paper. The total resistance of the circuit is R = 9 [ohms] and is constant. 1) what is the magnitude and direction of EMF...
  10. J

    Induced EMF and current in the circuit

    Homework Statement Homework EquationsThe Attempt at a Solution First I will label a few points . A is the point on the ring touching the rails , vertically below P . B is the point on the ring touching the rails , vertically below Q . T is the topmost point on the ring . M is the bottommost...
  11. J

    Current flowing in a branch in a circuit

    Homework Statement Homework EquationsThe Attempt at a Solution For calculation sake I will consider R = 1Ω . Final answer will be in mA instead of A . The middle two resistors 3R and 4R are in parallel , so I consider their equivalent resistance 12R/7 in the middle branch . In the left...
  12. Muhammad Danish

    Voltage Distribution in a Potential Divider Circuit

    Homework Statement Homework EquationsThe Attempt at a Solution When we will move the contact X towards P, the potential difference should be maximum across the potential divider. I work out A as my answer but I think it is wrong.
  13. J

    Two parallel diodes in a circuit

    Homework Statement Homework EquationsThe Attempt at a Solution I am not quite sure how to deal with the two diodes in parallel . How do we know what is the potential applied across the two diodes so as to decide which one is conducting ?
  14. J

    Engineering Rate of change of current in an R-L Circuit

    Homework Statement Homework Equations Current cannot change suddenly through inductor unless input is impulse voltage source. The Attempt at a Solution since input is DC source we have i(0+) = i(0-) so we have di/dt at t = 0+ is 0. Is it correct? Book has mentioned answer as B which is weird...
  15. D

    Two battery circuit charging one capacitor

    See attached photo for circuit diagram. The switch S has been open for a long time. Determine the magnitude of the electric charge stored by the capacitor. Use the following data: C = 3.43 mF, ε1 = 11.0 V, ε2 = 31.9 V, R1 = 3.66 Ω, R2 = 5.04 Ω. I understand how to determine the magnitude of...
  16. R

    Current Flow Through a Common Part of a Circuit (batteries and light bulbs)

    Hello, I have a simple question regarding current flow through a common part of a circuit. I encountered this as I am reading "Code: The Hidden Langauge of Computer Hardware and Software" by Charles Petzold. The images I've attached display what I'm talking about. I'd like to know if there's a...
  17. K

    Operation of this hydraulic circuit?

    Can anyone explain the operation of this circuit? I'm finding it hard to understand hydraulic circuits, like where is the source of fluid coming from? I know what all the components are and what they do. It's just trying to understand how it actually operates.
  18. F

    Find the initial current in the circuit (at t=0)

    Homework Statement In the circuit shown,the initial charge on the capacitor is Q0 = 200μC . If the switch is closed at t=0 , the capacitor starts discharging through the resistance R=4MΩ . What is the initial current (in μA) (i.e. at t=0) in the circuit? Homework Equations I = I0 e-t/τ τ =...
  19. A

    Finding the Optimal Combination of Resistors for a Desired Total Resistance

    Homework Statement I'm asked to find a combination of resistors (parallel and/or series) that uses resistors of 25 Ω, 100 Ω, 50 Ω, and 50 Ω. They should add up to give a total resistance of 62.5 Ω. Homework Equations Req for parallel = 1/R1 + 1/R2 + ... Req for series = R1 + R2 + ... The...
  20. F

    Find the time constant of the circuit

    Homework Statement In the circuit shown S is closed at t = 0 . Find the time constant (in s) if C = 2μF. Homework Equations τ = Req C The Attempt at a Solution R = ##\frac{10*10}{10+10}## R = 5MΩ τ = 5*106 * 2*10-6 = 10 s Could somebody check my answer?
  21. D

    Finding R(t) in discharging RC circuit

    Homework Statement A charged capacitor with capacitance C is being discharged through a variable resistor that has its resistance dependent on time: R = R(t). Find function R(t) if the current through the resistor remains constant until the capacitor is completely discharged and the resistance...
  22. D

    Calculating current in five resistor/two battery circuit

    Homework Statement The circuit above has five resistors. Calculate the current through each. Homework Equations I1 = I2 + I3 (Node Law) ∑Vi = 0 (Loop Law) The Attempt at a Solution I tried to equate the currents using the node law, with I3 = I1+I2+I4+I5 But I see a flaw here, because the...
  23. NYAME EPHRAIM

    The JK flip flop nand gate circuit that I built does not simulate

  24. J

    Engineering I don't know what this electronic circuit does

    I have a homework question that asks me to draw up a truth table for the attached circuit. As you can see I did this (I think correctly). There is also an attached question asking what function the circuit serves - I am not sure what function this is Any pointers appreciated.
  25. P

    Voltage drop conceptual questions

    I'm having trouble understanding how voltage drops. My understanding of voltage is a difference in potential, with potential being how much work is necessary to move a test charge to a specific orientation. So, if we have a circuit with say, a 12V battery and a 1 ohm resistor, and I had a +1...
  26. D

    High voltage circuit with voltmeter in between

    Homework Statement You have a voltmeter with an internal resistance of 10 MΩ. You would like to measure a very large voltage source, but you notice that this overwhelms your voltmeter, and you begin to get inaccurate results if the voltage is too high. You design the circuit shown above as a...
  27. G

    A Kirchhoff problem: Find the currents and voltages in this circuit

    Homework Statement In the circuit of the figure, determine the intensities I1, I2, I3, I4, I5 and the voltage Ug. Homework Equations Superposition and Kirchoff The Attempt at a Solution 20-10I1+5I3-10I1=0 5I3+Ug+5I5=0 20I2+10I2-150=0 From the last equation, 30I2 = 150, I2 = 5 A KNOTS...
  28. J

    Equivalent capacitance in a circuit

    Homework Statement Homework EquationsThe Attempt at a Solution I think the circuit given above is incorrect due to the presence of the two resistors . I have never seen/done a problem where equivalent capacitance is to be calculated across two points in a circuit , having resistors along...
  29. J

    Using Kirchoff's Loop Rule to Determine Currents in a Circuit

    Homework Statement Homework Equations Kirchoff's Rule The sum of all V = 0 The Attempt at a Solution [/B] I think I'm having a problem determining the current at r_2 and R_3. I had originally thought the currents at both resistors would be I_3, writing E_2 — r_2 I_3 — R_3 I_3 — I_1 R_1 = 0...
  30. E

    Equivalent resistance of a circuit

    Homework Statement Consider the electric circuit shown in the figure. Assume that V = 13.7 V, R1 = R2 = R3 = R4 = R5 = 7.00 Ω. What is the equivalent resistance of the circuit? Homework Equations total voltage of a series circuit is the sum of the voltage of all the resistors total current of...
  31. jdawg

    Engineering Heat and Mass Transfer: Thermal Radiation Circuit

    Homework Statement 1.) A piece of bread (ε = 0.85) is being toasted in a toaster, as shown below. The heating element of the toaster consists of a wire 2 mm in diameter that is wound to approximate cylinders spaced 2 cm apart. This element acts as a blackbody. The housing for the toaster is...
  32. E

    How to know when an LC circuit hits resonance

    I have been having issues with a series LC circuit. I have a supply voltage of 6.96 volts, across the inductor is 7.04 volts and the capacitor voltage is 7.17 volts. The capacitor has a capacitance of 45uFarad and a supply frequency of 250 hertz. I don't know what the inductance is of the...
  33. Paul Colby

    Voltage Monitor for an LC circuit

    Hi, I have an air wound 0.736 mH coil in series with a 3.5pF capacitor being driven with a function generator. Ideally the series resonant frequency should be around 3.13 MHz. The internal impedance of the function generator is 50 ohms or so. At resonance the voltage across the cap should be...
  34. G

    Engineering Determine the input impedances of a circuit

    Homework Statement I'm studying a circuit with BJT's and I'm asked to determine the input resistances of the two amplification steps of the circuit. The circuit I'm analyzing is the following one: Homework Equations 3. The Attempt at a Solution [/B] To determine the input resistances I...
  35. C

    Engineering Simple transformer circuit with 3 resistors

    Homework Statement 2. Homework Equations [/B] V1N2=V2N1 I1N1=I2N2 The Attempt at a Solution For a part[/B] I try to draw 3 mesh but I cannot write down the equation. Can someone help me out?
  36. H

    Find the transient current in this circuit

    Homework Statement Homework EquationsThe Attempt at a Solution I often do circuit. But still there is always stuff i don't get.. I was asked to find 1) I1 I2 I3 immidiately after S closed 2) I1 I2 I3 after sufficient of time 3) I1 I2 I3 immidiately after S opened Just give me clue please...
  37. D

    Engineering Problem regarding a transistor state in a NAND circuit

    Homework Statement Calculate the output function and draw a graph of output voltage in the function of the input voltage of the following digital circuit: Homework Equations 3. The Attempt at a Solution [/B] By analysis of what happens when inputs A and B are on the logical "1" i have...
  38. EF17xx

    Emf in a circuit (multiple choice question)

    Homework Statement Correct answer is Homework Equations emf = I(R + r) The Attempt at a Solution When current flows the voltage across the battery is less than the emf so it's not A I really don't understand why the answer is C because B, C, D all seem correct to me. Please help me with...
  39. S

    Circuit Diagrams versus Logic Diagrams

    Why do we sometimes neglect resistors and power sources when we draw circuits and other times not? Is there different terminology for diagrams that are only concerned about the logic involved and diagrams where the voltage and resistance is accounted for?
  40. C

    RC Circuit with parallel resistor

    Homework Statement A circuit contains a capacitor of capacitance C, a power supply of emf E, two resistors of resistances R1 and R2 , and a switch S2 . Resistor R1 is in series with the power supply and R2 is in parallel with the capacitor and the power supply. S2 switches the branch that...
  41. D

    Materials for DTL, TTL circuit analysis

    Hi fellow forum-ers :), I have a test in about two weeks where i am going to be given a dtl or ttl circuit which i have to analyse and calculate its function. The professor said that the circuit given to us will always be a useful and existing one meaning he's going to give us some NAND, NOR or...
  42. Muhammad Danish

    Current Dividing in an Electrical Circuit

    A circuit contains a 7.5V d.c power supply and three resistors. The total resistance of the circuit is 30 ohms. Why will the largest current in the 18 ohm resistor? As far as I know is that the smallest current will be in 60 ohm resistor because it has the maximum resistance. Please explain...
  43. J

    Equivalent resistance between two points on a circuit

    Homework Statement Homework EquationsThe Attempt at a Solution [/B] The circuit is symmetric about AC and BD , but I am not sure how to use this to simplify the circuit . Could someone help me in solving this circuit using symmetry considerations .
  44. S

    Engineering 2^k - 1 as Output of a Circuit with 3 k-bit Inputs

    If I have a circuit with 3 inputs with k bits, A, B and C, how can I get the output to be 2^k - 1 using relatively standard components? And, or, not, mux, decoder, adder, etc... This is for part of an exercise that I’m doing. I couldn’t find anything in the notes to help. Could anybody give...
  45. F

    Current in Series Circuit: .5A Charge Flow?

    If we measure the voltage in a simple series circuit to be 5v and the resistance to be 10 ohms. The current given is .5A. Is this the amount of chage traveling from the first point to the second point per unit time, or is it the amount of charge flowing through a cross section of the conductor...
  46. adamaero

    Engineering KVL and sensitivity of a simple circuit

    Homework Statement Homework Equations The Attempt at a Solution Note to self - simple diode concept: http://www.cs.tut.fi/kurssit/TLT-8016/Chapter3.pdf#page=5 Unsure about this KVL (above). For the last sensitivity part, equations be falling out of the sky...
  47. paulmdrdo

    Engineering Op-Amp Circuit Analysis: Troubleshooting Incorrect Node Usage

    In the problem below, when I use nodes V1 and V2 I get the correct answer of Vo = -2.5v But when I use nodes V1 and Vo I get an incorrect answer. Please explain to me why my latter method did not work. Thanks.
  48. T

    Hollow cylinder magnet making contact with the circuit

    Homework Statement 1. Circuit moves downward while cylinder magnet is fixed. 2. Cylinder magnet moves upward while circuit is fixed. Gain emf in circuit. Homework Equations All those maxwell equations... F=v x B The Attempt at a Solution [/B] So first question is not that hard...
  49. Valour549

    AC Circuit Analysis- Find Impedance

    Homework Statement 2. The attempt at a solution Am I doing something wrong? I know it's just voltage division with AC phasors and we have to equate the real parts and imaginary parts to find the unknown, but I feel like the question shouldn't be this hard.
  50. ForumGuy

    Can the Sum of Second Derivatives of Charges be Claimed in a CLC Circuit?

    1. The problem statement, all variables and given/known data Homework Equations Capacitor (C): v(t) = (1/c)*q(t) Inductor (L): v(t) = L(d^2q(t)/dt^2) The Attempt at a Solution Using Kirchoff's Loop law, the sum of voltages around each loop must be 0. I think I can thus claim the following...
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