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. Dor

    !Measuring Currents in a Circuit w/ Semiconductor

    If so, what will I measure in the Ampermeter, the zero total current or the value of the conduction current? I was thinking of the following example- a circuit consist of a current source, an Ampermeter, a switch, and a semiconductor. The semiconductor can have both conduction and displacement...
  2. Const@ntine

    Comp Sci PSPice Lab Exercise - Differentiator (Circuit)

    Look, this is a weird one, but I really need help. This is the Electronics Laboratory, that is supposed to be hands-on, but with Corona it got cancelled. However, they announced that we'd do it through the internet, had us download PSPice, and now we basically have to try and "translate" the...
  3. MARIAM507

    Electric circuit -- Ohm's second law

    I want to know ohm's second law i search many times about it but every time the result is about ohm's first only, so can anyone help me??
  4. tomdodd4598

    I The period-finding circuit for Shor's algorithm

    I've been trying to learn about Shor's algorithm by writing out implementations of the circuit for modular exponentiation, ##{ a }^{ x }\; ({ mod }\; N)##, to find the period ##r## for small numbers such as: ##(N=15,\quad a=11)\quad \longrightarrow \quad r=2##, ##(N=35,\quad a=13)\quad...
  5. S

    [AC Circuit] How do we convert from the time domain to the phasor domain?

    In this example, We need to covert e2 & e5 to a form with imaginary number . we will obtain e2=j10 & e5=20 Can anyone explain how we got this?
  6. S

    Current Induced in one circuit by another circuit

  7. henriquevpp

    Why this Simple Watt Meter for a 220 Volt Circuit works?

    Hello guys! I'm just a begginer student. I found this circuit of a wattmeter that works only with resistors. Can someone explain to me how the 33k resistor give a voltage of 1 mV to 1 Watt? I did not understand why these resistor values has been chosen and why the it measures only in the 33k...
  8. F

    Simulate open circuit and short circuit in MATLAB

    Here's my attempt: The results I got are close to the required answer, but there is a question telling: I tried to solve it, but Isc and Vt (in open circuit) are decreasing with the increase of the field current , so I didn't get the right answer. Could someone let me know where is my...
  9. F

    Engineering Simulate a step-down chopper circuit using LTSpice

    Simulate the circuit shown below sung LTspice.I tried to simulate it , but I didn't get the corrected result. Here's is my attempt: The result (voltage in the collector of the transistor) : Could someone let me know where is my mistake?
  10. dRic2

    I Resonant cavity and circuit analysis

    As I understand, if you solve the Maxwell's field equations for a resonant cavity, supposing a time dependence of the form ##e^{iwt}##, you get an eigenvalue problem and different modes as possible solutions. I'm reading some notes where the author states that each mode can be associated with a...
  11. kellys

    Help with this quantum circuit textbook problem about controlled gates

    Summary:: My skills are very very basic and I'm more a networking major but i had to take a quantum mechanics class, i have trouble with this xcercise from textbook quantum mechanics a general introduction [Mentor Note -- Thread moved from the Technical forums so no Homework Template is shown]...
  12. M

    How to calculate the efficiency of a switch mode power supply?

    I know how to calculate the power output and input by analyzing the current in put and output with multimeters and using the formula P=VI. But P_out is obviously incomparably smaller than P_in so the efficiency would suck this way. Is there a better way to do this??
  13. F

    Simulate a circuit diagram of a step-down chopper using Multisim/MATLAB

    Using Multisim or any Electrical Engineering software: I tried to simulate using Multisim, I got the output voltage. How to find the waveform for the current ? Could someone confirm my answer please? Any help is really appreciated .
  14. F

    Engineering Construct a circuit diagram of a step-up chopper in Multisim

    Using any Electrical Engineering software: I tried to simulate using Multisim, but the output voltage remains constant even after varying R1. Also, I only got the voltage from the oscilloscope, but how to find the current ? Here's my attempt: Any help would be greatly appreciated!
  15. C

    Can I simplify this RLC circuit problem using a different method?

    Hello, I have been thinking about this problem for a few hours, and I do not understand how I should proceed to solve it correctly. Section a is very simple, just substitute in the expression that gives us the values of L and C that the statement gives us. However, when I get to section b, I...
  16. B

    KCL got declined in Norton circuit of an ideal amplifier circuit

    Hi. Let's say we have a circuit like that, and we want to find the Thevenin/Norton circuit from a and b points. So for Vth, we calculate the Voc, in which we remove the 2K ohm resistor and calculate the Voc. I calculated it correctly. But I have problem in calculating the Norton current. So in...
  17. Wrichik Basu

    Electronics How to test whether the circuit board in a UPS still works?

    This UPS has been lying in the house for around seven years. We detached it from our desktop when it failed to provide backup. Six years back, I opened it up and found a swollen battery. At that point of time, I did not have any testing equipment, nor did I have any knowledge of electronics. So...
  18. M

    Two batteries and two resistors circuit - wrong possible answers ?

    It's ABCD question with answers attached. Problem is that, I don't think that neither of those are correct. From KVL the equation seems to be i = (E2-E1)/(2r1+2r2 + R). I've attached images of the circuit, answers, and my solution. Can someone please point me if I am wrong, and if yes, where's...
  19. T

    In short circuit condition, what is wrong with following derivation

    V=ir considering the whole circuit Now we knowV=E-ir Then ir=E-ir Therefore i=E/2r Therefore,V=E/2
  20. bornofflame

    Engineering Using KCL on this Op-Amp circuit to solve for V0 and I0

    Another classmate and a web search show that the answers for this problem are v0 = -12 V, and i0 = 2.4 mA. This was done using KVL around the circuit. I should be able to reach the same answer using KCL but I haven't and I'm not sure why. Is it because the source isn't connected to ground and so...
  21. Kaushik

    Equivalent Capacitance Between X and Y in this capacitor circuit

    This is the problem. If someone asks you this question, how would you solve it? I am finding it really tough to solve when the circuit gets a bit complex. It would be nice if you share what exactly you'll do to solve complex circuits such as this (the algorithm).
  22. jisbon

    Engineering Why Does My CMOS Circuit Fail to Pull Up?

    As attached below, I have drawn the step down and up diagram. However comparing to the answer, it seems to be way too off. Any idea why? Answer: Is there something wrong with my step down/step up circuit?
  23. J

    Voltage theory for an LCR circuit

    Summary:: I say the answer is A because these are reactive components that take and give back energy from the circuit so no voltage drop across the 2- L & C. Please let me know yours thoughts- thanks Hello I am a newby to electronics taking a class. Please review my thinking on this problem. I...
  24. B

    Equivalent resistor of a simple circuit

    Hi. Anyone knows how to calculate the Req of this circuit? n tends to infinite.
  25. Z

    Understand the Multi-party circuit: Priority Encoder

    Paper link is: MPCircuits: Optimized Circuit Generation for Secure Multi-Party Computation I have a question: What is the reason for using priority encode? The circuit diagram is given. I want to give some text from book: From the above text I want to understand why its a multi-party? It is...
  26. T

    Op-amp Oscillator Circuit Design (10-50 MHz)

    Questions: 1. Is LM741 capable of oscillating at 10MHz? If not, could you suggest me an affordable op-amp for this operation? 2. How likely am I, as a beginner to be able to design a zero phase shift feedback filter to use with a non-inverting op-amp circuit to create an oscillator? 3. If an...
  27. L

    Engineering Laplace transform of the given circuit

    Hello i have an assignment. From given circuit i need to find s domain and inverse them back to t domain. can you help me by explain this circuit?
  28. jisbon

    Engineering Constructing a CMOS AND circuit with MOSFETs

    Hi all :) So I constructed this based on a video tutorial, p, and n MOS, and was wondering if it was correct before I combine them. Also, it looks very different from what the proposed answer is. Since the equation is z=ab, The pull-down diagram looks like this: and the pull-up is z= a'+b'...
  29. bornofflame

    Engineering Solve for R1 and G in circuit with Vs, VCCS, and 2 resistors

    I've gotten to the point where I've hit a roadblock and am not sure what step to take next. I started by using KCL on the bottom node as suggested by the problem, then used KVL on the left mesh, but I still have ##i_{v_s}## which I'm not sure what to equate it to, so that I can pull it out of...
  30. jisbon

    Engineering Circuit Analysis Question (Truth Table, Logic etc.)

    Hi all, Having some problems digesting on electric circuits. Below is an example of a question and I would like to ask how do I go ahead in solving this. Firstly, for these types of questions: I have understood how to write a function table, and it goes something like this: Now what I am...
  31. F

    Construct a circuit with single phase asynchronous machine in MATLAB

    Construct the circuit above using the block shown below. The torque was gradually increased in small steps until the load torque reached the rated torque. At each step the torque, current speed, voltage and power factor was measured and the result record in Table (1). Tn = Rated torque = 1 Nm...
  32. E

    Could you show me a super capacitor's charging circuit? :(

    What is the fastest circuit to charge a supercapacitor?? could you show me??
  33. I

    Impedance of Circuit (Complex Numbers Question)

    Question is from Boas Ch. 2 Q.41 (I've the first edition) or Q 16.8 in the 3rd edition. Find the impedance of the circuit shown (R and L in series, then C in parallel with them). Circuit is essentially this (it is a closed circuit which I can't easily draw). -----R------L--- -------C---------...
  34. jisbon

    Circuit Analysis - Source Transformation

    My work seems to be wrong somehow since my answer is wrong, and I need your help to find out which part is going wrong for me :/ My work: 1. 2. 3. 4. 5. 6. (10/7)/(10/7+7) = 0.7627A, which is not the answer. May I consult where is the problem in solution? THanks
  35. jisbon

    Circuit Analysis Question -- 2 sources and 4 resistors

    Now, I know this question can be solved using Kirchoff Voltage rule, but the question expliciitly wants me to use power supplied = power absorbed. Hence taking V0 to be x, I can't still seem to calculate. Any ideas? Power supplied = (60)(3) + (5x)(3) = 180+15x Power absorbed = 72+ 56 +28 + 3x...
  36. halleff

    Signal Speed Below the Speed of Light for Circuit Abstraction

    I've read a couple of other topics on the Physics Forums about the lumped circuit abstraction requiring that signal timescales (i.e. the period of the highest frequency signal component) be much longer than the propagation delay of the signals though the circuit and that the wavelength should be...
  37. C

    Reluctance of a bar magnet circuit?

    If you hold a bar magnet in the middle of an empty volume and put a gauss meter in front of a pole, there is evidently a measurable magnetic flux, so there is a magnetic circuit there. What is the reluctance of the whole circuit, not counting the bar magnet itself? How do you work that out? Is...
  38. T

    Electrical potential energy questions for a battery circuit

    I’m trying to learn about simple circuits but I have a few questions because I don’t fully understand what’s going on . 1. If the reason current flows when a wire is connected to the ends of a battery is due to a potential difference across a battery , why can’t the current just flow through...
  39. T

    Why do you need a line 2 on an Alternating Current circuit?

    Preface to thread: The power source in both diagram 1 and diagram 2 is a wall outlet with alternating current power, not a battery. The load in both diagram 1 and diagram 2 is a light bulb, even though I forgot to label the load in diagram 2...
  40. P

    Engineering How Can I Use Simetrix to Verify My Amplifier Circuit Calculations?

    I have calculated my own solution but I am struggling to work out how to use Pspice to compare my values. I am using simetrix for this - could anyone help with this part? My solution is: VGS = -IDS RS Av = Vo/Vi Vo= -gm VGS RL Vi = VGS (1+gmRS) gm= IDS/VGS so gm= IDS/-IDS RS = 1/RD = -1/100 =...
  41. J

    In an LC circuit the current does no drop to 0

    in an LC circuit the current does no drop to 0 but varies sinusoidally. The capacitor is recharged with a different polarization. Why is this so?
  42. L

    How does this capacitor circuit not violate conservation of charge?

    There must be something I'm not understanding about capacitors in series. I know that we can treat them as one equivalent capacitor with: (1) with 1/Ceq, (2) same Q as anyone of the capacitors, (3) and add up the Vs for the sum total V across them. If the equivalent capacitor (Ceq) would...
  43. J

    Find EMF of a battery in this circuit

  44. B

    Kirchhoff's law: Circuit problem with multiple batteries and resistors

    Struggling to see if I am doing this right or not from a section of a question I have been given I have drawn out a sketch of the circuit again, and labelled as to what my 1st and 2nd closed loop to be to then apply Kirchhoff's 2nd law I get a negative I_2 current which just indicates that...
  45. Sokolov

    Maximum voltage that can be applied to DC circuit with resistors

    I see that ##V_{ac}=V_{ab}+V_{bc}##, with ##V_{ab}=I_1R_1=I_2R_2## and ##V_{bc}=I_3R_3##. However, I don't see how to express mathematically the maximum value of ##V_{ac}##. Could someone please help me with this task?
  46. V

    Find the expression for Power in circuit

    I was wondering if someone could check my answer and see if it is correct. The resistance in series is Req= R+ R= 2R The voltage across 2R is the terminal voltage V. The expression I get is: Can I also use this formula P=I^2*R? When using it I get: Current through the resistors is The...
  47. Prabs3257

    Heat dissipated in a Resistor-Capacitor circuit

    I tried to conserve the charge on the left plates of both the capacitors as intially the total charge on both is 48 and at t=t0 the total charge is 36(on c1) +4V(V is the potential across c2) so i got V=3 and then i conserved the energy Initial energy on both capacitor = final energy on both +...
  48. V

    How to calculate the equivalent resistance in this Circuit?

    I start from far right: Green and blue are parallel Connection: This in turn is in series connection with black resistor: and so on ... This is what I'm ending up with My final equivalent resistance is (275/17) Ω. Is this correct?
  49. engnrshyckh

    Finding the fault in this circuit (UV lamp controller)

    Guys this circuit and shematic is of UV lamp controller.. It burns sometime as shown in figure can someone tell the reason?
  50. lottotlyl

    Engineering Calculate R and C in Envelope Detector Circuit (AM Modulation)

    1. Add impedance in parallel of capacitor and resistor Z_rc = 1/((-wC/j) + 1/R) = (jR)/(j-wRC) 2. Ohm's law for relationship of i_d, Z_rc, and Vo Vo = i_d * (jR)/(j-wRC) Unsure how to do the rest? Thanks.
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