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. Bling Fizikst

    Doubts on Diodes: Circuit Solving

    What do i need to do for transfer characteristics for the first problem (B)? I plotted the ##V_1## and ##V_2## plot on the same graph: Is it correct? For the second problem , i guess the capacitor ##C_1## is just there to ensure AC flow . But really unsure how to approach this .
  2. mkamalzayed

    Analyze this circuit with 2 sources and 4 resistors

    How does the current flow in this circuit and what is its actual true path, regardless of any directions in the figure? What does the “5i” above the dependent source mean, and does the current flow according to the dependent source or the independent source? Are the two resistors 2 ohms and 6...
  3. N

    Low Voltage level problem in STM32 system chip

    Dear all, hope you are doing great. I am designing a circuit using EasyEDA simulation tool. But I am facing a problem after connecting the relay to the single-Chip IC (STM32 103RTC6). The low voltage is showing around 2V, whereas it was originally supposed to be 0 volts. I am still unable to...
  4. N

    Determining the Change in Bulb Brightness by Changing Circuit

    I understand that removing bulb E will cause the equivalent resistor to change in the circuit. This change will cause the current across the circuit to change (which will either brighten or dim the bulbs). I found that R_eq (with E) is 1.167. R_eq = [1 + (1/1+1)]^-1 + [1 + 1]^-1 = 1.167 I...
  5. MatinSAR

    Circuit with time varying current

    The picture of the question and my try: Would it be possible for someone to double-check my answer for accuracy? I would greatly appreciate any feedback or guidance on this matter.
  6. L

    Parallel RLC circuit complex impedance graphing

    ^^ as mentioned in the homework statement, the relevant equation is my worked out impedance for the circuit. I have attached a diagram of the circuit below.
  7. tellmesomething

    Circular argument? Justification of equipotential points

    I read the solution which stated that ADB and ACB branch are symmetrical. Therefore D and C are equipotential. However this feels like a circular argument when im saying that the branches ADB and ACB are symmetrical, im imagining this circuit without the DC branch. And then im using my previous...
  8. tellmesomething

    Electrostatics and current problem with 3 metallic balls

    Theres a picture of the circuit attached. I did not understand how to start the problem since we dont know the distance between the terminal A and the sphere to write the absolute potential at terminal A. So I looked at the solution and im afraid I dont understand it at all. The teacher took...
  9. BuggyWungos

    Why is current constant through a resistor?

    I understand that the current in the top wire above A will be the same as the wire just below A, as it will be for the wire region marked by n to m, due to the fact that all current in equals all current out. My confusion lies in the first equation I supplied, the change in voltage through the...
  10. tellmesomething

    How does a simple circuit work?

    I am going to reason this out for a simple circuit with a battery (with no internal resistance) and connecting wires which can be considered perfect conductors. Please let me know if I am thinking correctly, I am quite confused by the overall working. An isolated battery has two electrodes...
  11. tellmesomething

    Why is the current in a conductor equal to zero when not connected to a circuit?

    Can someone provide me with a justification on this? As fair as I know current through an area is the rate of transfer of charge from one side of an area to the other. So how does current become 0 in a conductor (not connected to a circuit just a plain conductor) just cause "the number of...
  12. F

    Can Coax-Wound Coils Prevent Radiation in Ferrite Core Magnetic Circuits?

    Assume i want to create a magnetic circuit within a ferrite core with airgap (i need the B field in airgap). The ferite core would have a coil on it. Problem is if i want my core airgap area and magnetic path length longer than wavelenght of current through the coil i would have high losses as...
  13. Nabir14

    Can We Make PCB Using Paper And Pencil?

    I had a question in my mind about PCBs. Printed Circuit Board (PCB) is a non-conductive material with conductive lines printed or etched. Electronic components are mounted on the board and the traces connect the components together to form a working circuit or assembly. Now a Pencil has...
  14. S

    Small alarm system circuit analysis

    TL;DR Summary: Hey, I was hoping for some help on how I would be able to calculate the minimum and maximum frequency that can reached with the potentiometer and also how this circuit works intuitively, because I don't really understand it. Thanks in advance! Hey, The TL;DR sums it up. I don't...
  15. M

    B The total voltage drop in a series RLC circuit

    my textbook said this which I don't think is true, tho the textbook still said this (this equation is the true one) so is the textbook right about the first equation?
  16. B

    Is This a Series or Parallel Circuit?

    Consider the problem below I used Kirchoff's loop/junction rules to correctly arrive at answer C (1.3A). Before using Kirchoff's rules I tried to get ##V_3## by treating this as a Fermi problem using the following lines of logic, but there is a flaw somewhere, can someone identify the flaw...
  17. E

    What explains the current flow in a LC circuit?

    I'm just not able to grasp the concept of a LC circuit intuitively, and yet I have found zero answers to my doubts. I can't understand why does the current keeps flowing counter-clockwise between the 3rd and the 4th circuit (see image attached) I know that when the capacitor has 0 charge, in...
  18. mishima

    Help me understand cheap boost module?

    Hi, I recently acquired some of these cheap modules for plasma experiments. I tried dissolving the epoxy off of one of them in an attempt to reverse engineer the circuit. I can see a resistor, diode, and transformer but am unsure about some of the other components. I was wondering if anyone here...
  19. S

    Calculate voltage over capacitor and resistance

    Hi! I tried by using the Thevenin. Later using Vth and Rth to calculate Vs(0.1ms). After that I divided the voltage from E over R1 and R3. The circuit and my attempt:
  20. rampantschess

    Circuit design using switches puzzle

    TL;DR Summary: I am trying to design a circuit using juat a power source, 3 switches (1,2,3) and 3 Resistors (a,b,c) and wires. i want to design the circuit so it satisfies 4 conditions. the first being if all switches are on, the 3 resistors have current flowing in parallel, second, if only...
  21. Tofuwu6

    Final Charge of a Capacitor in a Circuit with Capacitors and Resistors

    I had two trains of thought. One is that the capacitor will fully charge when t = infinity, so when you plug t = infinity into the equation of charge as a function of time you get 1.68E-4, which you also could've gotten from Q = CΔV where ΔV = 42V. My other train of thought was that when t =...
  22. Shauryafrom2006

    I can't understand this circuit board

  23. leVanw

    I found this circuit board in an old toy car. What does it do?

    I found this circuit board in an old toy car. Does anyone know what it is for and how to use it?
  24. M

    Amplifier gain in resonant RLC circuit

    Amplifier gain ##A_V## is defined as the ratio of an amplifier's output voltage to its input voltage, i.e. ##\displaystyle\frac{V_R}{V}=\frac{IR}{IZ}=\frac{R}{R}=0.5## at 200 Hz. But this is absurd. Where have I gone wrong? Please nudge me in the right direction.
  25. E

    How Is a Power Recliner Wired for Multiple Functions?

    As far as I can tell there are three circuit states that control the recliner foot rest, raise it, lower it, and off. How is this wired, how does the switch function etc...? I assume the up and down switch flip the polarity across the motor, but that is all I can seem to reason out...
  26. S

    Circuit calculation practice: voltage dividers, series, parallel

    Hi, I'm teaching Engineering (honors) and want to drill the students on series, parallel resistors in circuits and voltage dividers. does anybody a have a worksheet with lots of samples? Thanks!
  27. SCHROEDERFPM

    Beginner circuits / ↓ the voltage & ↑ the efficiency

    So far this is what I have: I have the power source, two triple in a battery case, negative to the T emitter, T output to the (-) of motor, T base through a resistor to the switch, switch to the (+) of motor. I tried wiring the Led to this junction and the switch, but either the motor or the...
  28. ZoeDale

    Engineering Basic circuit problem about BJT and buzzer

    I don’t understand what does the v_t mean?
  29. kplee

    DC blocking the photodiode signal

    Hi all, I was trying to detect small optical signal through amplification process and realized that there is a huge DC background behind the AC signal. So I decided to remove the background using a Thorlabs DC blocker (EF500). The photodiode I used was Newport 818-bb-21, and the signal before...
  30. skibidi

    Kirchhoff's law: Find the current I3 through the Amp meter

    I separated the circuit into parts- upper and lower For the upper loop I wrote: -14-2I1-3.4I3-I2 = 0 For the lower loop I wrote 16-2.9I2+3.4I3-5.4I2 = 0 I solved for I1 and I2 separately and plugged it into the junction rule and solved for I3. I may have got it wrong because of the...
  31. L

    Engineering Show a resonant curve in a simulation between 800hz and 4.5khz

    i have created the circuit but i am not sure what to do from here, this program is new to me
  32. H

    Comp Sci Quantum computing circuit for qubits equality

    This is the given circuit: I think to add another Cnot on the right with a1 as control and a0 as target, to set initial states of a0 an a1 both |0⟩, and to measure the a0. If a0=|0⟩ then b0=b1, and vice versa. Is it correct?
  33. student_man

    Engineering Current change after inserting thin conductive foil into resistor

    I tried splitting it up into 4 individual resistors, adding them up (each side serially and then both sides with each other as parallel) and then using V=IR but it ended up being the same current as the original. (The answer should end up being (9/8)* the original current)
  34. L

    Engineering Produce a resonance curve for this circuit between 6 kHz and 10 kHz

    this is what i created so far, but not quite sure how to get the resonance curve, i tried to enter it in settings and do an AC sweep
  35. L

    Engineering Create a circuit in simulation to prove my work (2 batteries and 1 lamp bulb)

    so this is a question i am trying to solve and then confirm with the simulation, so far i have.. Lamp load IL = PL/VL 1/6 = 0.1667A Thevenin resistance Rth = Rs1 || Rs 2 = 2 x 4 / 2 +4 = 1.333ohms Vth = 12V look at node voltage with load circuit and use kcl V = 6V Is1 = 12 -6 / 2 = 3A Is2 =...
  36. S

    Brightness of two lamps in a circuit having a changing magnetic field

    The answer key is (D) but I don't understand how to approach this question. I am guessing the wire is acting as short circuit path but how to know which bulb will be short - circuited? Thanks
  37. S

    Correct energy transformation about circuit with EMF, a resistor and a motor

    My answer is C (although I am not sure if the correct one is C or D). I suppose since the 1-V battery is being charged by the 9-V battery, the electrical energy should be on the RHS of the energy transformation. Am I correct? Thanks
  38. J

    A circuit involving two non-linear resistances (incandescent lamps)

    In the circuit, two identical incandescent lamps are connected to a voltage source of voltage U = 6.0 V via an ohmic resistor of magnitude R= 8.2 are connected to a voltage source of voltage U = 6.0 V. As electrical components, incandescent lamps do not behave like ohmic resistors. When current...
  39. phyzguy

    Recognize these inrush current limiting devices?

    I have a circuit board, and one of these inrush current limiting devices (yellow arrows) has failed. Does anyone recognize them? Failing that, does anyone recognize the logo that looks like a letter V and an upside down V superimposed? I have searched in several places, but have been unable...
  40. S

    Calculating low frequency cutoff for this R-C microphone circuit

    I want to ask about question (c). My idea is to compare the period and time constant. The period is 0.05 s and time constant is 0.005 s. Time constant is the time needed for capacitor to discharge until the charge stored in it becomes 37% of initial charge. But I don't know how to relate the...
  41. PhysicsTest

    How Does a Capacitor Introduce Phase Delay in a Circuit?

    I simulated the below circuit to capture the phase delay between input voltage and output current in LTSpice How do i measure the phase delay introduced due to capacitor?
  42. E

    I have a question about diodes and the PN junction

    Is the PN junction inside a diode what makes the electrical current only flow in one direction and not in the opposite direction? If this is so, why does it happen? Also Why is the P-type material said to have empty holes and the N-type material to have free electrons?
  43. L

    How Do You Calculate Capacitance in a DC Circuit with a Fully Charged Capacitor?

    Hi, I am not sure if I have calculated the task correctly I have now assumed that the capacitor does not need to be charged and is therefore fully charged. In a DC circuit, a capacitor acts like an infinitely large resistor or like an open switch, so I assumed that it is a parallel circuit...
  44. Edy56

    Engineering Thevenin Generator: Maximum Active Power & Calculation

    So I have calculated Zab which is 3-3j (it's correct). Now I have to calculate (Uab)0. This is where I just get completely lost. In my opinion: (Uab)0=E3+I3*R3+Ic1*Xc1+E4 Note: I recognize these currents are not shown in the picture, but based on their indexes and basic logic I hope you...
  45. core7916

    Which Circuit is Best for Sampling Voltage and Current in the 250V, 30A Range?

    Hello, Please help me to create the sampling processing circuit. i have to create the voltage and current sampling processing circuit, Then the output of circuit will be fed to processor to further operation. output voltage of my original circuit will be maximum 250v and current is 30A(peak...
  46. V

    Find equivalent resistance R in the circuit

  47. V

    Find the equivalent resistance between two points in terms of R

  48. L

    Engineering Frequency Response of High-Pass Filter at 1kHz

    use a frequency range from 10 Hz to 10 kHz and show that the circuit operates as a high-pass filter with a ‘knee’ point at 1 kHz I have to be honest i an not 100% on what the question is asking me, should i be working out Frequency resonance first using all the information provided, then i need...
  49. lukakopa7

    Battery protection circuit board

    Does anyone know a cheap(available on Ebay/AliExpress ) battery protection circuit board that has undervoltage/overvoltage protection and charging capability? I have a 3.7v Li-po battery and I need to draw 5 Amps from it.
  50. V

    Potential difference between 2 points in a capacitor circuit

    In the given circuit, a transient current will flow and when this current finally stops at equilibrium, the charges ##q_1## and ##q_2## are assumed to deposit at the capacitor plates as shown below. The dashed line indicates an isolated system that will have it's total charge conserved. If I...
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