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).

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  1. T

    Breaking down a complicated resistance circuit

    Homework Statement Homework Equations - The Attempt at a Solution I tried to break it down to: But apparently it is incorrect, can someone tell me the correct configuration? And explain too! Thanks :) (Please do not give ambiguous "hints").
  2. lbwet

    What's the total resistance in this circuit?

    Homework Statement https://imgur.com/3H3pCkD R is the resistance of each resistor, determine total resistance in the circuit. (see the image in the link above) Homework Equations R=1/R₁+1/R₂+1/R₃+... (in parralel circuit) R=R₁+R₂+R₃... (in series circuit)The Attempt at a Solution I'm...
  3. E

    Engineering Opamp Circuit Q: Find Vo in Terms of Vs | Chegg.com

    Homework Statement http://www.chegg.com/homework-help/questions-and-answers/ideal-opamp-find-v0-terms-vs-need-help-solving-vp-firstly-understanding-parts-q8278769 Homework Equations I am having difficulties with this problem. It asks to find vo in terms of vs. For the gain, I got an...
  4. D

    How to calculate the resistance in a combined circuit

    Homework Statement Work out the total resistance of a combined circuit. https://gyazo.com/935b96ff63689e2bff852f29ea48bf90 - picture of circuit layout Homework Equations Rt=R1+R2+Rn... R=V/I 1/RT=1/R1+1/R2+1/Rn... The Attempt at a Solution RT=R1+R2 =100+150=250Ω for the resistors in series...
  5. A

    Engineering Combination Circuit Diagram (resistor network simplification)

    How do I accomplish this? The goal is to redraw the diagram of the ciruit shown below, until it becomes series in the end. Given: Here’s what I did: Diagram 1 2 3 4* 5 *I apologize for flipped images. iPhone camera is tricky. Is this correct? If not, why?
  6. T

    Find the equivalent model of an infinite ladder circuit

    Homework Statement 2. Homework Equations Ohm's law and Kirchoff's voltage law The Attempt at a Solution My solution is a bit long so I will just briefly explain it. First, we find the total equivalent resistance. Since the circuit extends to infinity, it is equal to replacing the second...
  7. F

    Electric potential and voltage in a circuit

    As I understand it, electrical potential is the potential energy of a unit charge in some point in space. How does this idea relate to the idea of voltage in a circuit? The term electric potential seems to be used for both.
  8. D

    How to calculate resistance in a combined circuit using V&I

    Homework Statement I am not sure how to calculate the resistance of the circuit and each resistor using voltage and current. I know how to work the resistance out in series and parallel but am 100% how to work it out in combined. Homework Equations R=V/I, 1/Rt=1/R1+1/R2 The Attempt at a...
  9. Manoj Sahu

    Difference between a circuit breaker and a load break switch?

    Hi. I am working in on a Ring Main Unit of Siemens make. Today, my senior asked me the same question. As per my understanding, a circuit breaker is make or break switch. I mean, when fault occurs the circuit breaker trips, protecting the equipment connected to the line. I have no information...
  10. Muhammad Usman

    What is the Significance of the Electric field in a closed circuit

    Hi, I am confused about the electric field lines which are depicted mostly on the Internet as per conventional way. What I understand that the conventional current was due to positive charges which was wrong. Actual flow of the current was due to the negative charges or electrons. When the...
  11. G

    Engineering Biasing circuit with a MOSFET: am I missing something

    Homework Statement I have the following circuit with MOSFET (cascode amplifier). [![enter image description here][1]][1] [1]: https://i.stack.imgur.com/BAqQh.png Information given: ##V_t=1V## ##I_1=20\mu A## ##k=10 \mu AV^{-2}## Knowing that ##V_b## is 5V determine the minimum value of the...
  12. tensor0910

    Engineering Determine the current in this circuit

    Homework Statement Find the current Ig[/B] Homework Equations [/B] V1 = R1/(R1 + R2) * Vs 1/Rtotal = 1/R1 + 1/R2 + 1/R3...exampleThe Attempt at a Solution I know what I did wrong, but I don't know how to avoid it. Here's what I mean. How do you know which way its suppose to be?
  13. kcombs

    Solve RC Circuit Problem: Find Time of Current > 50mA

    Homework Statement Suppose a 120 micro-farad capacitor from a camera flash unit retains voltage of 210 V when an unwary student removes it from the camera. If the student accidentally touches the two terminals with his hands, and if the resistance of his body between his hands is 1.8...
  14. D

    Why is my calculated resistance higher than the resistor used

    Homework Statement Why is my calculated total resistance of the circuit higher than the resistor used in series and the theoretical total resistance? In a series circuit I used a 100Ω resistor and measured the current at 1.0v intervals from 1.0-5.0v. At 1.0v the current was 8.70mA using a 100Ω...
  15. N

    Engineering Find the equivalent resistance of this circuit w/o Data?

    Homework Statement Find the equivalent resistance of this circuit between points a and b https://imgur.com/a/LWcIC Homework Equations The Attempt at a Solution I am not sure how to complete this problem without any variables. I tried replacing the numbers with the variables which is what I...
  16. tensor0910

    Engineering Circuit diagram: find the equivalent resistance

    Homework Statement problem in title:Homework Equations 1/Rtotal = 1/r1 + 1/r2...[/B]The Attempt at a Solution [/B] I can get it down to 4 resistors...but the one's I have circled I don't know how they behave. I just need a little kick in the right direction lol. Thank you in advance!
  17. A

    Why isn't a capacitor an open circuit?

    I understand the basics of how capacitors work. If you hook one up to a power source, negative charge will build up on one plate, and positive charge will build up on the other plate. As the charges build up, an electric field forms between the plates and a potential difference is established...
  18. A

    Strange charging voltage behavior in a resistor-capacitor circuit

    hi, i tried to simulate a simple capacitor and resistor charging circuit like this i used an imaginary resistor value "10M ohm" the result as you see appear to be strange, why this happened? is capacitor's charge is relative to the voltage on the capacitor it self? and i need some...
  19. A

    Lemon Battery Voltage: Why More Resistance?

    So I was messing around and made a lemon battery using a zinc nail and a copper penny. I wired 4 of these lemons together and connected it to a 5mm red LED and got around 3.7V. It came on but was dim. However, when I wire my power supply and also set it to 3.7V, it is much brighter. Now i assume...
  20. M

    Current in circuit with many resistors

    Homework Statement Find the current and potential difference through 3Ω resistor. Homework Equations ε - I1 (Ω) - I2 (Ω) ... = 0 The Attempt at a Solution I only got as far as finding the equation: ε - I1 (3Ω) - I2 (16Ω) = 0 (For complete loop around circuit) I know I have to find I1, but I...
  21. E

    Engineering Basic circuit problem -- Resistor network and a voltage source

    Homework Statement http://www.chegg.com/homework-help/questions-and-answers/problem-2-variableh-resistor-r-circuit-fig-p224-adjusted-va-equals-60-v-find-value-r-q8083343 Homework EquationsThe Attempt at a Solution Hi, I attached a pdf file with the problem. My question is, for the lower right...
  22. M

    Voltage Output in subtractor photocircuit

    Hello All, I work in an optical lab and am currently attempting to determine the voltage output of a subtractor circuit I've wired up (as I'd like to work back from my output voltage and FFT magnitudes to read out the value of a magnetic field using faraday magnetometry.) So my circuit is as...
  23. G

    Engineering Inductor circuit time constant

    Homework Statement Hi. I started studying LR circuits and the first thing that made me do searches in textbooks of mine and in the internet was the time constant which is surprisingly not L times R, but L/R which would mean the time needed to store and release energy is being prolonged with...
  24. T

    Hall Effect in an alternating current circuit

    Since the classical Hall EMF is proportional to current, in an alternating current circuit, the Hall Emf should also follow an alternating pattern. Is it so? Or the Hall Emf doesn't change in a sine wave pattern instead remains more or less same and has a voltage based on the average/rms...
  25. E

    Engineering Part C: Solving Resistance in a Complex Circuit

    Homework Statement Part C of the following problem http://www.chegg.com/homework-help/questions-and-answers/problem-1-find-equivalent-resistance-rab-circuits-figp36-q8156743 2. Homework Equations The Attempt at a Solution Hi, to solve this problem, first i tried to ignore the two resistors...
  26. F

    Discharge in a DC RC circuit and Kirchhoff's Loop Rule

    Hi all, I think this issue periodically resurfaces in PF. I have found a similar discussion in this closed post and possibly others. I'm posting this because I'd like to check my understanding, if anyone is available to provide some furtherinsight. So I'm trying to gather a "overall"...
  27. E

    Engineering Help with finding the power in this circuit

    Homework Statement http://www.chegg.com/homework-help/questions-and-answers/interconnection-fig-p25-valid-find-total-power-developed-circuit-interconnection-valid-exp-q22345911 It asks if the circuit is valid, which I assume it is. It asks for the power developed[/B]Homework Equations I tried...
  28. R

    Synchronous Generator Short Circuit - Hazards

    What are the possible hazards and causes of short circuit internally in a synchronous generator?
  29. M

    Hi, can somebody explain this RLC circuit to me?

    Hello to everbody can you help me how come C6 to be 10p and c5 13.5 and and l1 to be 190n and L6 240n i start with 100Meghz, with one circuits 50/XL or 50/XC now become three different thanks i understand the first circuit, i understand the second circuit, but now they make three circuits how...
  30. A

    Questions about Using My Multimeter

    So I'm fairly new to electronics. I took physics 2 in college and thought I'd give the hobby a try. I started with a very basic circuit. Just a power supply connected to a light-bulb. However, as simple as it was, I had several questions when taking the reading of my circuit with a multi-meter...
  31. ace130

    Analyze this opamp active filter circuit

    Hello, so this the circuit of an IdeaI OPAMP. The Question is to find the function Vs/Ve . I tried to make some sum ups to simplify it but I still unable to find a solution, so I tried to NOT sum up any component and found this: E-S=iZ+i2(Z+R) E=iZ+i3R S=i2R so the idea is to find E=f(i2) ...
  32. W

    Weak measurement quantum circuit

    Homework Statement The circuit in the attached photo has a one-qubit operation ##U## which is controlled by the first qubit. The box with the meter and arrow denotes a measurement. If ##U=H## what is the probability of finding 0 or 1 in the final measurement of the second qubit? Homework...
  33. C

    How to find the energy of capacitance?

    Homework Statement Find the energy in the 2uf capacitor in the diagram attached in uploads. Homework Equations E=(1/2)CV^2 E=QV C=Q/V Capacitor in series : 1/(Equivalent Capacitor) =Σ1/(Ci)* Capacitor in parallel: Equivalent Capacitor =∑Ci* *i is the index of summationThe Attempt at a Solution...
  34. G

    Engineering Thevenin's equivalent circuit for capacitor

    [Mod Note: Thread moved from technical forum hence no homework template.] Okay so the image i uploaded only because of the cirscuit never mind the text to it. I don't understand things mathematicaly verry well. I like to have a good physical grasp on what is going on with the circuit. That...
  35. D

    Engineering Calculate the effective values in this 3-Phase Circuit

    Homework Statement Given the known quantities ##R, C, L##, ##k##, and the effective values of the voltages ##E_1=E_2=E_3=E## , ##w = \frac{1}{\sqrt{LC}}## of the direct-symmetrical 3-Phase system find the expressions for the effective values of ##U_{12}##, ##U## and ##I## and calculate the...
  36. J

    Engineering Inverter Circuit Turn Off Time

    Homework Statement Solution in Book#1 Solution in Google: [/B] 2. Homework Equations I don't know which solution is correct. I am struggling to remember this formula. The Attempt at a Solution This was a solved example so I didn't attempt.
  37. J

    Engineering Transient RC Circuit (got answer in s but not in t-domain)

    Homework Statement Homework Equations Vc = ( Initial Voltage - Final Voltage ) e(-RC/t) + Final Voltage 3. The Attempt at a Solution I got the answer through Laplace but am not getting through time domain analysis. Given q across C is 2.5mC C = 50micro F q = CV So V = 50V Initial voltage =...
  38. E

    I with this circuit -- 2 resistors and 2 sources....

    Homework Statement The problem is in this link https://www.chegg.com/homework-help/find-vo-io-circuit-fig-226figure-226-chapter-2-problem-7pp-solution-9780078028229-exc Homework Equations 3. The Attempt at a Solution [/B] 15=[io/3]+[io/3]+ [vo/12] I got this equation for the problem...
  39. D

    Engineering Calculating the effective value and frequency of AC Circuit

    Homework Statement For AC Circuit shown in the picture, ##C=60nF##, ##L=100uH##, ##X_3=-100Ω##, ##Z_2=50Ω## and ##Φ_2=\frac {\pi}{6}##. When the switch is closed the ammeter shows a current ##I_1=0.6A## and the voltmeter shows ##U_l=60V##. The measuring instruments mentioned are ideal...
  40. Nabin kalauni

    How can I design a circuit for my project?

    I am a first year high school student designing a project. I want to build a circuitry that enables wet clothes to enter the house once it starts to rain. For this I decided to use a simple water sensor and a motor to move the rope with clothes. But after that I have not found a satisfactory...
  41. H

    What's the current from this circuit? Is it a short circuit or not?

    Homework Statement Pic A, what's the I2? Pic B, what's the current across a-b ? Homework Equations V = I*R Voltage in series is different, the current is the same Current in parallel is different, the voltage is the same The Attempt at a Solution from Pic A, I found that I1 = 1A, I3 = 1A...
  42. T

    Can a radio frequency be lowered by a passive circuit?

    Is it possible to design an unpowered antenna, (possibly some kind of RLC circuit) which will receive a radio wave at a particular frequency and then re-emit it at a lower frequency?
  43. Richie Smash

    Explain How the Lamp in Circuit A Lights When Switch S is closed

    Homework Statement Hello Everyone, a pleasant good morning to all :) I will attach an image that shows a diagram of a circuit. The question based on this picture is as follows: ''When switch S is closed, the Lamp L, lights. Explain how this occurs.'' Homework EquationsThe Attempt at a Solution...
  44. T

    How can each Coulomb of charge transfer energy

    regards my question is how each coulomb of charge can lose (transfer ) energy when going from a to b when electrons are very slow the definition of potential difference: is how much each coulomb of the charge loses (transfer ) energy when going from a to b an example to clarify the question...
  45. sumit_1

    Understanding Charge Flow in RC Circuits: A Scientist's Perspective

    I have a RC circuit which also includes a battery, the capacitor has some charge initially before we put all the components in the circuit. Now as I connect all of them then charge will start to flow, but wheather this charge will be the sum of initial charge on the capacitor and the new charge...
  46. 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...
  47. M

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

    can somebody tell me this circuits calculations, how come 10mA please
  48. 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!
  49. 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...
  50. 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...
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