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. paulmdrdo

    Engineering How were tangent terms derived in solving for eqn (2) in a second-order circuit?

    I was trying to follow the solution for this problem and got stuck in the last portion of the solution. I encircled the part that I did not understand. I can't figure out how the solver was able to come up with tangent terms. Please enlighten me. TIA
  2. Zeynaz

    LDR circuit electricity question

    So far what i figured out is that R2 and R3 are in parallel, R1 and LDR in parallel. And these two parallel circuits are parallel to each other ( tell me if I am wrong) The voltmeter has to read 0 but I am not sure how i can achieve that. Is there a rule where when the resistance of each side...
  3. M

    Diagonal Series/Parallel Circuit

    I got my test back and was reviewing my question, to find out that I didn't even solve for R2,R3,R4 Current, correctly. I only got 2.613A correct which was R1, could anyone possibly help me out. I know for parallel circuits voltage drop is equal across circuit but my R1 was in series with the...
  4. paulmdrdo

    Engineering Why Does a Second Order Opamp Circuit Show Contradictory Derivatives?

    I was trying to understand the way this problem was solved and I got confused with the latter part of the solution. I encircled the part that confused me. They seem to contradict each other. If dv(0+)/dt = 0 why is it dv(0+)/dt = -1 in the other one? Please explain. TIA...
  5. fight_club_alum

    Kirchoff's law and circuit analysis

    I assumed the current flows from the 20V so, 20V - 100 (i1) - Ri2 = 0 First loop 20V = 100i1 + Ri2 Second loop +Ri2 + 40V - 200(0.08) = 0 Ri2 = -24 Back to equation 1 20 v = 100i1 + (-24) therefore, i 1 = 0.44 For loop two: i1 - i2 = i3 0.44 - i2 = 0.08 therefore i2 = 0.36 ohms...
  6. Zack K

    How exactly do inductors work in an LC circuit?

    I understand Faraday's law and about induced electric fields created by a changing magnetic fields, etc. But what causes the current to oscillate in an LC circuit, with no battery? If you picture that there is current going into an inductor, and that current is decreasing over time, then you...
  7. C

    Is this an AC/DC converter circuit?

    I found this circuit (attached images) in an insulated pouch inside my basement's smoke detector compartment. It gets power from the hot line that feeds my smoke detector, and outputs power to a mystery load through a second outgoing romex wire (no idea where it goes). All my smoke detectors...
  8. Rasias

    How to calculate what a voltmeter measures with multiple resistors?

    I tried to solve it by removing the voltmeter and simplifying it to just one resistor, then calculate the individual volts and then the deltaV, but still didn't found the answer, can you guys help me?
  9. paulmdrdo

    Engineering Solve 2nd Order RLC Circuit Problem | Get Answers Now

    I was stuck with the last line of my solution please help me find the correct answer to this problem. TIA!
  10. bobg123

    Engineering Circuit input impedance with ground in an OP Amp circuit

    I've been given the following circuit and have been asked to find the input impedance and the impedance between the input terminal and ground. I've never encountered an operational amplifier configured like this. I know that the voltages at the - and + terminals of the op amp are ideally equal...
  11. D

    Engineering Question on basic circuit analysis

    My initial attempt had me combining the 40 and 20 ohm resistors in series, then combining the result with the 120 ohm resistor in parallel (top). However, this was incorrect. According to my answering guide, the correct method was to transform the voltage source into a current source, then...
  12. S

    Engineering DC source rather than a clamper circuit?

    Why is it preferred to use a clamper circuit rather than a DC source to shift an AC source upwards on a voltage-time graph?Both require a battery(DC source) so isn't it cheaper than having to use some extra elements like capacitors and diodes?
  13. H

    How is the energy of a zero resistance circuit converted to rotational energy?

    If I have a DC induction motor coil of a zero resistance so that means that to sustain a constant magnetic field I do not need any energy. So in a DC motor how is energy of zero resistance circuit converted to rotational energy of a motor?
  14. H

    In a car ignition how does a circuit work?

    As I get it is that after the contact breaker breaks the contact then the current flows from plus of the battery through the primary winding then through the capacitor and to the minus of the battery. But then what happens to the secondary current? It goes from secondary coil and then what? Does...
  15. R

    Finding the ODE that describes this circuit + find its transfer function

    As you can see, I've tried using KCL at node A to find the 2nd order ODE that describes this circuit in terms of the capacitor voltage. The problem I run into, however, is that I can't find anything to put the node voltage at A in terms of. I've tried (not shown here) doing mesh current as well...
  16. D

    Total equivalent resistance of a combined circuit

    I attempted to solve the problem by following the positive terminal of the battery and I realized that Resistor R1 has a different path than R2+R3+R4. I came to the conclusion that R1 is in parallel with R2+R3+R4. The series connection with R2,R3,R4 would be 30 ohm total by adding the three...
  17. Wrichik Basu

    Free circuit simulation software/website for beginners

    I was looking for simulation softwares that are free. I looked at some on the net, but they aren't satisfying my basic requirements. A simulation software should at least have the following for my use: Arduino support Support for buck converter Solid state relay Transformer Variable AC supply...
  18. M

    Why Do We Need an External Voltage in Photodiode Circuits?

    I am a bit confused on a few things regarding photodiodes. Here is are two circuits that I am referring to: or For the second circuit the capacitor is not of importance. Here are my fundamental questions: 1. Why do we need an external voltage? 2. Why do we need a resistor? 3. What is...
  19. A

    LaTeX Excluding circuittikz, how can I create circuit diagrams

    Hello. I want to create circuit diagrams, excluding the package tikz and not wanting to write up a schematic in latex, how can I create circuit diagrams? I would think one of you would have been creating and importing complex diagrams into latex. I do not want to take pictures and post them, I...
  20. SaiTatter

    I need to calculate the equivalent resistance

    Homework Statement The circuit is the one in "Fig.4" I need to calculate equivalent resistance between A and B. This is what I've tried: I think that the first resistor is shorted by that wire connected between A and E. Their answer looks like this, in fig 2.2.1. I'm not sure if their...
  21. MedEx

    Finding the Current in a Resistor in a Closed Circuit

    1. Homework Statement The ideal battery in Figure (a) has emf = 7.7 V. Plot 1 in Figure (b) gives the electric potential difference V that can appear across resistor 1 of the circuit versus the current i in that resistor. The scale of the V axis is set by Vs = 18.9 V, and the scale of the i...
  22. paulmdrdo

    Engineering RC-RL Circuit: Solving for Capacitance Value

    Homework Statement [/B] 2. Homework Equations 3. The Attempt at a Solution In got stuck. I'm not sure as to what Time constant should I use to solve for the capacitance value. In the original expression for the current, both terms are exponential function. I do not know whether to...
  23. Zack K

    Mesh Analysis Method for Finding Current in a Circuit with Dependent Source

    Homework Statement Find the current in each resistor. (refer to uploaded diagram) Homework Equations ##Kirchhoff's Law: I_s=I_1 + I_2## Mesh analysis method The Attempt at a Solution I'm calling ##I_s## the total current before and after the current splitting up, and ##I_1## and ##I_2## are...
  24. Z

    Engineering Amplifier circuit driving an 8 Ohm speaker

    Homework Statement Hi all. I need a bit help with the following. Estimate the power developed in the 8 Ω speaker of the circuit of FIGURE 2 for a 1 kHz sinusoidal input signal of 100 mV peak. All capacitors may be assumed to act as a short circuit at the frequency of operation. Compare your...
  25. Toolkit

    Engineering How Can I Correct Errors in My Circuit Mesh Analysis?

    Homework Statement Homework Equations I've worked out the KVL's for four meshes, I1, I2,I3, and I4. Would anyone be able to error check this for me? Also, would I be correct in thinking that I can use ohm's law by dividing V1/Z1 to find the current of the first mesh and likewise with...
  26. Kenny555

    Ohmmeter question -- Measuring a 2-resistor circuit

    Homework Statement [/B] Find reading of ohmmeter. Homework Equations V=IRThe Attempt at a Solution I am a beginner of this topic and I think it is simple as ohmmeter directly measure the resistance of the resistor which is 2k ohm while the correct answer is 1.67k ohm. I have no idea how to get...
  27. L

    How to introduce a phase shift in an AC circuit

    Hello, I am trying to think of a way to introduce a phase shift in an ac circuit. For example, sin(omega*t+theta) to change theta. How can I go about doing this? I do not think introducing a cap or inductor would work, even though it shifts the voltage from the current graphs (phasors). A...
  28. J

    Finding the Current in a circuit

    Homework Statement The diagram below shows a circuit where; R1 = 5.0 Ω, R2 = 8.0 Ω, R3 = 1.0 Ω, V1 = 16.8 Volts, V2 = 1.5 Volts, and V3 = 39.6 Volts. What is the value of I1? In solving this problem, initially pick the current directions as shown. If the actual current turns out to be in the...
  29. hagopbul

    Asking about the Vcc of some integrated circuits

    Hello: I have to ask some question , did anyone know any integrated circuits that have voltage Vcc of few kilo volts what was the catagoeries of that circuits ? And do they different from high current integrated circuits ? Where to read about it ? Best hope
  30. R

    Finding the values of voltage and current in this circuit

    Homework Statement It's best if one looks at the picture of the circuit diagram. What we're given is a current of 0.25 A and two resistances of 20 and 30 ohms. Homework Equations Kirchhoff's Voltage Law, Kirchhoff's Current Law, Ohm's Law The Attempt at a Solution My attempt at a solution...
  31. T

    What is the potential at point D in the circuit

    Homework Statement I've attached a picture of the circuit below for reference, but the question is asking what the potential is at point D.Homework Equations V = IR[/B]The Attempt at a Solution I was told that the answer was 9V, but I'm a little confused because I thought if I looked at the...
  32. Abdullah Almosalami

    Constant Current Source in Driving an RC Circuit

    Alright. So I'm getting two different solutions depending on how I look at this problem, and I know one is correct but I don't know why the other would be incorrect. So, given this general circuit of a constant current source driving an RC circuit in parallel: Now, what they tell me in class...
  33. Boltzman Oscillation

    Engineering What is the output voltage of this ideal diode circuit?

    Homework Statement Given the following circuit: what is the positive and negative peak values of Vo? vi has a frequency of 1kHz, peak of 5V, and is a sine wave. Homework Equations x(t) = Vsin(2(pi)*f*t) KCL, KVL, etc. The Attempt at a Solution [/B] I made Vi to be 5sin(2(pi)1000t) during...
  34. M

    Engineering Nodal analysis of an AC circuit

    Homework Statement Hi I have this question as part of my assignment but cannot get my head around part b, I have worked out part a with an answer of -9.2+17.3i amps which from a previous thread I know is correct, but can't understand why the equations given in the previous thread are different...
  35. S

    Correct statement about series RC circuit

    Homework Statement The battery is disconnected from a series RC circuit after the capacitor is fully charged and is replaced by an open switch. When the switch is closed, a. the capacitor does not allow current to pass b. the current stops in the resistor c. the potential difference across the...
  36. J

    B Help with math in a quantum circuit

    Hi! Sorry for the bad English! I'm trying to get a better understanding in quantum mechanics by doing the math of quantum circuits and I'm stuck! So, please, if someone can, help me! =) I'm trying to the math of this circuit: q0 ... l 0 ) .... x ... (I) q1 ...
  37. R

    Please could someone critique my circuit schematic (simple)

    Hi, I am just putting a simple representation of my equipment in a type of circuit schematic as part of my set-up figure. Please could someone who is more experienced than myself tell me if there is anything wrong with it / any suggestions. Thanks in advance for any help...
  38. Jason-Li

    Thevenin's Theorem, Superposition & Norton's Theorem

    Homework Statement FIGURE 1 shows a 50 Ω load being fed from two voltage sources via their associated reactances. Determine the current i flowing in the load by: (a) applying Thévenin’s theorem (b) applying the superposition theorem (c) by transforming the two voltage sources and their...
  39. Boltzman Oscillation

    Engineering How to analyze a circuit with one node using the node method

    Homework Statement I have the circuit given below with a single node where R3 and ground meet. How can I solve this problem using the inspection method? Is it possible? I can easily solve using another method but I would rather try using the inspection method. Homework Equations Ax = M A is...
  40. E

    Puzzled by how the Voltage is the same across different points

    If this is better for the HW section please tell me, sorry about that. So Voltage is the change in potential. I'm puzzled by how potential in circuits is the same along different points until we reach a resistor - at which point the potential changes. As in, if we take two points before a...
  41. dvscrobe

    Engineering Time Constant of an Opamp Circuit

    Homework Statement : [/B] Find the time constant of an inverting op amp with C = 50uF, Ri = 200 Ohms, Rf = 20 Ohms. This is a problem I have found in a prep book for the Fundamentals of Engineering Exam (Electrical component). The book gives the answer as time constant = Rf * C. I am not...
  42. Eduardo Leon

    Energy dissipated in the resistors in a 2 mesh RC circuit

    Homework Statement Hi mates, I have problems solving the third part of this exercise, I've already done all the previous calculations. Given the following circuit, where the switch S is open, the power supply = 50 volts and: The initial charge in the C capacitor: QC = 0 coulombs The initial...
  43. F

    Engineering What Is the Correct Probability Calculation for a Quantum Circuit Measurement?

    Homework Statement input state is |1>(tensorproduct)(2|0>+|1>). Homework Equations Find the probability of the outcomes being 0 and 1 measuring the second qubit. And then what the outcome states of each are. The Attempt at a Solution I have attempted this problem and for the probability of...
  44. Shivang kohlii

    Time constant for parallel RC circuit

    Homework Statement Question 6. Homework Equations Time constant = RC The Attempt at a Solution I think answer should be 1/2 RC as Rnet = 1/2R and to convert it to single resistance form we should first find Rnet But the answer is coming out to be RC . How? << Corrected Image added by...
  45. Z

    Help Understanding Circuit Requirements for Conducting Diode

    Hi all. I need some help with the circuit attached. For the diode to conduct, at point X the voltage must be 0.6V minimum. There is an equation to find the minimum required voltage input, Vin to give 0.6V at X. What I don't understand is the right hand side of the equation; why is it...
  46. DLeuPel

    Calculate the voltage in a circuit

    Homework Statement Given the following circuit, find the values of V1 and V2. Homework Equations The second law of Kirchhoff states that the sum of all voltajes must equal 0 The Attempt at a Solution I found in the book that the solution is V1: 15V and V2: 14V I tried to solve V1 by adding 9...
  47. dothep6

    Does a series circuit have branches?

    Does a series circuit have branches? or the term branch can use in series circuit too and there are only one branch in series circuit. please explain.
  48. F

    Engineering Design a logic circuit to add two 2-BCD decade numbers

    Homework Statement Homework Equations - The Attempt at a Solution Here's my work : When I added 0000 0001 to 0000 0000 , I didn't get the correct answer . Could someone check where is my mistake please ?
  49. F

    In a circuit, what causes current to go from L1 to L2?

    The photograph above this sentence is a photograph of a simple 2 leg circuit of alternating current with a light switch and a light bulb. I know how alternating current constantly switches direction from line 1 to line 2 and then goes from line 2 to line 1, etc. In the diagram in the above...
  50. I

    Calculating Short Circuit Current: Tips & Advice

    Good evening to everyone! I'm pretty new in this kind of job, so every help or advice will be helpfull and I will appreciate it. I know that short circuit current from picture in attachment depends on impedance and reactance of Source MV, transformer example (10kV/0.4kV) and cables. So if I...
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