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. K

    Current division in a series-parallel circuit

    Homework Statement Determine the current through each circuit element Homework Equations V = IR (Ohm's Law), The Attempt at a Solution I1 is .06A after plugging 6V and 100 ohms into V = IR, but I can't figure out the rest, because I don't know how the current splits. The left path obviously...
  2. J

    Engineering Designing 3-Stage Async Counter & Logic Circuit in PSpice

    Homework Statement The block diagram of FIGURE 3 shows a three-stage asynchrononous counter that is used to count a series of randomly occurring input pulses. The ‘Q’ outputs of the counter are used to drive a logic circuit that gives the output shown in TABLE 1. (a) Design the counter using...
  3. A

    Circuit Problem -- Combining 4 resistors to make 95 Ohms

    Homework Statement 1. Use resistors of 30 ohms, 40 ohms, 50 ohms, and 50 ohms to create a circuit with a total resistance of 95 ohms. 2. Find the amount of current going through two of these resistors if the circuit is attached to a source of 12 v. 3. What would be the voltage drops for the...
  4. Polygon

    I Electrical circuit differential equation

    q''+ 20 q = 100 sin(ωt) I have been asked to find all mathematically possible values of ω for which resonance will occur. From the homogeneous solution, q(t) = Acos(√20 t) +Bsin(√20 t), I can see that resonance occurs when ω=√20. My question is, should I also consider -√20? And if so, what is...
  5. doktorwho

    Help understanding phasor solution

    Homework Statement From the given circuit and provided information draw a phasor and calculate the inductance. Homework Equations 3. The Attempt at a Solution [/B] The paper was given to me at class as a solution to our homework and i can't understand how they drew the phasor and drew the...
  6. D

    Engineering Laplace tranforms, transient current series CR circuit

    Homework Statement A step voltage of 120v is applied to a series CR circuit. R = 20KΩ, C = 4µF 1. Deduce, using Kirchoff's voltage law and Laplace Transforms, an expression for the transient circuit current. 2. Using the equation obtained in 1. deduce the equations for the transient voltages...
  7. T

    Gain of Electric Circuit: Vo/Vs and Resistance R

    Homework Statement So this problem is on Introduction to Electric Circuits 9th Edition (Richard C.Dorf) This asks me to express the gain of this circuit Vo/Vs by terms of the resistance of R. Homework Equations KCL, KVL, some ideal OP AMP characteristics... The Attempt at a Solution...
  8. Alexander1

    Voltage Regulator Circuit Calculations

    Hey Guys, so I'm just in need of some help in relation to finding the output current after the voltage has been dropped to 6V. The circuit has an input voltage of 24V and I've attached a photo of my circuit diagram. Hopefully I haven't made any errors in that, but I've tested the circuit and it...
  9. F

    Engineering Solve Series RC Circuit for Capacitance & Currents

    Homework Statement Three lamps are rated 110 V, 60 W. They are connected in parallel and a capacitor is connected in series with the group. The circuit is then connected to a 230 V 50 Hz power supply. Detremine: a) The capacitance which is required to provide the correct voltage across the...
  10. B

    Opamp Circuit: Finding Voltage at Resistor and Power Supplied

    Homework Statement Homework Equations V_- = V_+ The Attempt at a Solution There is negative feed back so V- =V+ ... Vout is then equal to the voltage at the positive terminal So the solution does a voltage divider... finding the voltage at the 4.62 ohm resistor.. However I did KCL at...
  11. C

    Engineering Model of RL Circuit using the Energy function

    Homework Statement From the textbook: We define an energy function \begin{equation} V(\textbf{x},t) \leq 0 \end{equation} for the system \begin{equation} \dot{\textbf{x}} = \textbf{f}(\textbf{x},\textbf{u},t). \end{equation} The function V may be the total energy of the system, or it may be...
  12. Ravensight

    Engineering Finding unknown Phasor in a series-parallel circuit

    So this is a "bonus" question from a past final exam for my Electrical Circuits course. I've spent a good few hours trying to solve it but haven't really had much luck. Any method can be used I figured if I found the voltage of the known XL, it would be equivalent to the voltage of the unknown...
  13. Z

    Simple effective resistance of a circuit at low voltages

    I passed small voltages (0-5V) through a known resistance, measured the current each time, and got different "effective resistances" for each case. However, when graphed, the effective resistances appear to approach the known resistance of the circuit as a limit at higher voltages. What is the...
  14. e0ne199

    Engineering Question about free source RLC circuit

    Homework Statement below is my question : Homework Equations all of the equatios used to solve this problems are equations for free source RLC circuit. The Attempt at a Solution so far i have solved problem (a), whose answer is -1400V/s, the problem is when i want to solve (b) and (c) do...
  15. S

    Capacitor Circuit: Understand 40µF Capacitor

    Homework Statement 2. Homework Equations [/B] No equations needed The Attempt at a Solution I know that capacitors are used to store charge but what exactly is the 40 micro-farad capacitor doing? No emf/voltage is shown so is the 40 micro-farad capacitor acting like the emf/voltage? or is it...
  16. Manoj Sahu

    What does IC555 do in this circuit?

    This is the circuit diagram of a solar charge controller. This circuit is fed by a wind mill or a solar photovoltaic panel. Either wind mill or solar PV panel work at any instant controlled by switch SW1. I don't understand what is the working of IC555 here. The main objective of this circuit is...
  17. Tyler R

    Solving KVL in a Multiloop Circuit with Battery & LC Circuits

    1. The problem statement, all variables, and given/known data I built a multiloop circuit for a project. The 4.2v is from mini-USB. The 3.7V is a lipo battery. The circuits are A/V Transmitters (LC circuit) which have an impedance of 75 ohms. The resistor is a 470-ohm resistor. I don't think...
  18. C

    Writing Kirchhoff Rules for a Multi-Loop Circuit

    Homework Statement I need to write Kirchhoff rues for the following circuit. This is not for a physics class, but for a programming class. I can do that part, but I am not sure if the equations are correct. Homework Equations The Attempt at a Solution V1-I1*R1-(I1-I2)R3-I1*R2=0...
  19. Vanessa Avila

    (LC Circuit) Finding cap charge after connecting to inductor

    Homework Statement A capacitor with a capacitance of C = 5.95×10−5 F is charged by connecting it to a 12.0 −V battery. The capacitor is then disconnected from the battery and connected across an inductor with an inductance of L = 1.50 H . What is the charge on the capacitor after a time...
  20. Cocoleia

    Laplace transforms in circuit analysis, finding missing values

    Homework Statement The Attempt at a Solution At this point, usually I would replace the values and sometimes separate into partial fractions, and then take the inverse Laplace transformation. So I know that the inverse Laplace needs to give me 6+12e^-2t. I am given the answers in my...
  21. Kara386

    I Why Does No Current Flow Between C and D in This Circuit?

    In the circuit in the image attached, why does no current flow between C and D? I've been told it's a short circuit I just don't see why, there is a resistor in that branch. The source is connected between terminals A and B.
  22. Cocoleia

    Using Laplace to solve circuit analysis

    Homework Statement The Attempt at a Solution As you can see, the answer is given in the problem. I have the 0.8t par right but somewhere along the way I messed up. I'm not really to sure about how to solve these types of problems using Laplace. Is there a general procedure that I should be...
  23. Manoj Sahu

    Will this solar charge controller circuit work?

    The circuit is intended to control the charging of a 12v 7ah battery by a 10w, 24v volt solar panel.
  24. S

    Type of circuit -- What would you call this?

    Homework Statement Homework Equations No relevant equations The Attempt at a Solution Trying to figure out what type of circuit this is. As far as i can tell its just a circuit with voltage, inductors, and resistance and a switch Only thing is i don't know what type of circuit this would be...
  25. D

    Engineering Simple DC Circuit Analysis with Transistor

    Homework Statement Homework Equations The Attempt at a Solution All loops are clockwise; KVL Loop around 1V, 120kOhm and VBE (I1 is assigned to the loop): -1V + 120kOhm * I1 + VBE = 0 I1 = IB = 0.3V / 120kOhm = 2.5 * 10-6 A; Loop around 10kOhm, vCE (I2 is assigned to the loop); KVL...
  26. TheBigDig

    Engineering Finding Phase Difference in an RC circuit

    Homework Statement Homework Equations ##V = ZI## ##Z_R = R## ##Z_C = -\frac{j}{\omega C}## ##Z = \sqrt{R^2 + (\frac{1}{\omega C})^2}## ##P_{av} = \frac{1}{2}V_m I_m cos(\phi)## ##\phi = arctan(\frac{-1/\omega C}{R})## ##\Delta \phi = \phi _1 -\phi _2## The Attempt at a Solution I've found...
  27. T

    Dumb question regarding short circuit test equivalent resistance

    Hi, Silly little question about the transformer short circuit test. When I perform it with the secondary shorted and I get Req = Power / current2 is this Req = Rpri + Rsec? If I measured Rpri and Rsec with a multimeter? Thanks
  28. S

    Solving Inductor Circuit Homework Problems

    Homework Statement For the circuit shown in the figure, the inductors have no appreciable resistance and the switch has been open for a very long time. (Image of circuit) (a) The instant after closing the switch, what is the current through the 60.0-Ω resistor? (b) The instant after closing...
  29. Manoj Sahu

    Circuit Explanation: 12V CFL and LED Usage?

    I stumbled upon this inverter circuit while searching for the same on internet. Can anyone please explain working of this circuit to me.
  30. A

    Why do the capacitors in this circuit have the same voltage?

    Homework Statement Homework Equations C = Q/V The Attempt at a Solution I understand that capacitors in parallel have the same voltage, but wouldn't they be in series after the switch is flipped, since no current goes to the left most portion of the circuit.
  31. R

    Plotting a RLC Circuit: Analyzing a Differential Equation

    I'm not sure about the physical behavior of a RLC circuit and I have to give a presentation that involves one. So I've decided to plot the current. I found a book that gives a differential equation to describe the circuit. ##L\frac{d^2i}{dt^2} + R\frac{di}{dt} + \frac{1}{C}i = \frac{dv}{dt}##...
  32. stephen8686

    B VIR Chart for Circuit Analysis: A Quicker & Intuitive Alternative to Loop Rule

    Hello guys, I'm reviewing for the AP physics C exam and in one of my review books I came across this trick called a VIR chart for circuit analysis. It's a sort of weird alternative to the usual Loop Rule. If you haven't heard of it before here it is...
  33. ltnghia1304

    How to find the open circuit voltage?

    Homework Statement How can we find the open circuit voltage of this one: Thank you Homework EquationsThe Attempt at a Solution
  34. nothing909

    Engineering Capacitor in a switching circuit

    Homework Statement This is a switching circuit for a switched reluctance motor. At the right hand side of the circuit attached below, there's a 47μF capacitor. What is the need for that? The attempt at a solution Is it to reduce harmonics or ripple, or something of the sort?
  35. paulmdrdo1

    MHB Natural response RL circuit

    as you can see In the image I provided I have derived the equation for i(t) and v(t). On circuit A I use a passive sign convention(current flowing from positive to negative) on the inductor, hence the equation and their corresponding graph. i(t) is decaying exponentially, v(t) is decaying...
  36. paulmdrdo

    Natural response RL circuit

    as you can see In the image I provided I have derived the equation for i(t) and v(t). On circuit A I use a passive sign convention(current flowing from positive to negative) on the inductor, hence the equation and their corresponding graph. i(t) is decaying exponentially, v(t) is decaying...
  37. AHMEDbr

    Engineering Temperature compensation circuit

    Homework Statement I am designing a local oscillator ( clapp ) whose frequency needs to be kept constant even with varying temperatures , this oscillator have an output frequency 150 MHZ , and power supply 3.3 V Homework Equations which temperature compensation circuit must be used with this...
  38. O

    How to solve the differential equation for driven series RLC circuit?

    Homework Statement It is the driven series RLC circuit. It is given in the following images. It is from the section 12.3 in this note. Homework Equations The differential equation, as given by 12.3.3, is ##L \frac{d^2 Q}{d t^2} + R \frac{d Q}{d t} + \frac{Q}{C} = V_0 \sin{(\omega t)}##...
  39. M

    Setting up a circuit to drive a Laser Diode

    Hello fellow physics friends (alliteration: always a strong opener). I am writing today because I find myself struggling to complete something which ostensibly doesn't seem that difficult to the average physics undergrad working in a lab. However, electronics and circuits are definitely a...
  40. S

    Engineering Rectifier Circuit - Guidance requested

    Homework Statement I have an unregulated power supply circuit consisting of the following: Transformer, 10:1 ratio, 230VAC rms 50Hz incoming voltage Full Wave Bridge Rectifier Filter Capacitor, 1000μF Load - Resistor, 25Ω Find the following: 1) RMS & peak voltage across secondary winding of...
  41. L

    Finding internal resistance & EMF of a battery in a circuit

    Homework Statement When an external resistor of resistance R 1 = 14 Ω is connected to the terminals of a battery, a current of 6.0 A flows through the resistor. When an external resistor of resistance R2 = 64.4 Ω is connected instead, the current is 2.0 A. Calculate the emf and the internal...
  42. P

    Low DC amp through small circuit of 14 AWG copper wire?

    I have a 2 AMP regulated DC power supply, with variable voltage 3 - 12 v. If in a small circuit, i.e, small copper wire with 1 ohm resistor. Why am i not getting at max Amps?
  43. K

    Electricity -- Effect of heating a thermistor in this circuit

    Homework Statement The thermistor is heated so that its resistance decreases. State and explain the effect this has on the voltmeter reading in the following positions. A–C Homework Equations V=IR[/B] The Attempt at a Solution :[/B] I will say that the voltage will increase because if the...
  44. B

    Circuit that reverses the flow of current to a motor

    Hello, I am building a small car that upon hitting a wall will go backwards, in other words reverse the current flow. I have all the components requiered (resistors 3k and 1k, wires, 6V battery, and an H-bridge, locking button) only thing I do not know is how to connect them all together. If...
  45. victor94

    I Help in understanding a quantum circuit

    I'm in a proyect to simulate quantum circuits in robots like in this paper ( http://ieeexplore.ieee.org/document/4215941/ ) ,the first thing that i need to do is to simulated the circuit that is in that paper: But I'm having trouble understanding how the hadamard gate affects the "C"...
  46. Ali Zain

    Rank in order, from largest to smallest, the resistance (eq)

    Homework Statement There is a figure, I'll try my best to draw/describe. 1. All three resisters are in parallel ___R____ !___R____! !___R____ ! 2. 2 resisters are parallel and one in series, after the parallel (ignore the dots) ___R___ ... _____R___ !___R___ ! 3. 2...
  47. Z

    Seemingly unstable basic PIC18F2550 circuit

    From my work I've had quite a bit of experience with hardware development, but purely from a supervisory role, and so recently I've been playing around with ground up MCU circuit design to try to get a better understanding. I put the following circuit together to allow me to play around with...
  48. M

    Source Free RL circuit confusion

    1. The problem statement, all variables, and given/known data I have a single loop RL circuit with no source. I am given the the inductance of 3mH, as well as that energy storage is as follows 1 J @ t=0 and 100mJ @ t=1ms. No current is given. I have to find R. I don't need the answer just some...
  49. The_Inventor

    Circuit Board Design: Basics of Designing a PCB

    My background is in physics so I have a very basic understanding of circuit design. I was just wondering, If someone were to design a printed circuit board (from scratch) how do they know that it will function the way it should? and also how do they know that the printed circuit board will...
  50. B

    Conceptual Understanding for Voltage in a Circuit

    I'm having trouble understanding circuits, particularly voltage. So my question is more of a conceptual dilemma. Please correct my definitions and relations if it is incorrect. Voltage is the energy provided per charge, and this energy is converted to KE once the circuit is closed, or in other...
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