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. A

    Engineering Find the time constant for this RC circuit, help please

    Homework Statement Homework EquationsThe Attempt at a Solution
  2. Lapse

    Engineering Finals Study Time A Two Source Circuit w/Inductor, Cap, and Resistor

    Homework Statement Homework Equations Z = √(XC2 + XL2) XL = 2πƒL XC = 1 / 2πƒC I = V/Z The Attempt at a Solution First off, thank you for all of the help this semester. I'm sure you'll be seeing questions from me in the spring also. Here is how I'm thinking about this problem: 1. Using the...
  3. R

    LRC Series Circuit Critical Damping

    Homework Statement Homework EquationsThe Attempt at a Solution My attempted solution is above and here https://imgur.com/8RmDMf8/ I'm confused as to the answers in the book being i and iii (I just don't see how i is included). If critical damping occurs at the value above, and if you go above...
  4. S

    Engineering Solving a Circuit with a Complex Source

    Homework Statement An image of the problem is attached. I need to solve for ic(t) and vc(t) by adding a complex source. Homework EquationsThe Attempt at a Solution I don’t know where to start here. I don’t understand the question, and I can’t find the information I need in my notes. Can...
  5. L

    How to Determine the Resistance R1 in a Mixed Circuit Analysis?

    Homework Statement The following circuit is given, and all voltage, current, resistance and power must be found for each resistor. I have found the following information: Vsrc = ? Isrc = .5A Rsrc = ? Psrc = ? V1 = ? I1 = .5A R1 = ? P1 = ? V2 = 2.5V I2 = .25A R2 = 10 P2 = .625W V3 =...
  6. Y

    How do you analyze this circuit

    This in not homework. I am playing with this circuit and I don't understand what is not right. Here are the circuits. a) I "built" an opamp out of U6, U7 and U8. I set the gain to 21 by R6/R3+1=20+1=21. The output is OUT1. But I get a little more gain than expected, like 22 or 23. b) I use...
  7. F

    Engineering Draw the equivalent circuit using only NAND gates

    Homework Statement For the circuit shown below , draw the equivalent NAND gates . Homework Equations - The Attempt at a Solution Could someone check my answer please ?
  8. H

    Open circuit voltage of an old battery

    Why the voltage of an exhausted battery, in open circuit state, is almost identical with that of new battery? The internal resistance of an exhausted battery is very large and so, the large amount of energy consumed by the source (for overcoming the electric filed in the battery) would waste in...
  9. sneakycooky

    Find the charge q(t) for an LC circuit

    Homework Statement An LC circuit consists of an 82 mH inductor and a 17 microfarad capacitor that initially carries a 180 microC charge. The switch is open for t < 0 and is then closed at t = 0. a. Find the frequency of the resulting oscillations. b. At t = 1 ms, find the charge on the...
  10. e0ne199

    Engineering Problems about Zin in complex circuit analysis

    1. Homework Statement the problem is my answer for question (a) is not the same as the answer provided by the question, i get 2.81 - j4.49 Ω while the answer demands 2.81 + j4.49 Ω Homework Equations simplifying the circuit, details can be seen below The Attempt at a Solution...
  11. Nikhil Rajagopalan

    Charging and Discharging of a capacitor in an LC circuit

    In an LC circuit, the capacitor that is initially charged to a finite value starts to discharge cross the inductor, initially the current increases and the inductor opposes it, but as the current is supplied against the back emf, due to the discharging of the capacitor, won't it reduce the value...
  12. Boltzman Oscillation

    Engineering Derive expressions for the voltage gain of this opamp circuit

    Homework Statement Derive the expressions for the voltage gain (Gv) of the following op amp: Homework Equations In = Ip = 0 Vp =VnThe Attempt at a Solution I can use KCL, and the fact that In and Ip are both 0, to derive the two equations, one from the top node and the other from the...
  13. Shivang kohlii

    Current through source in AC circuit with R & LC in parallel

    Homework Statement In the circuit diagram shown , Xc = 100 ohm , XL = 200 ohm , R = 100 ohm , the effective current through the source is ? Homework Equations Z= √( R^2 + ( XL - Xc)^2) Vrms = Irms/ ZThe Attempt at a Solution I tried to draw the phaser diagram and calculate the relation...
  14. archaic

    AC Circuit and Thevenin's theorem

    Homework Statement I'm asked to find the thevenin equivalent circuit, the load being ##R_1## ##e(t)=E_0\cos{(\omega t)}## ##R_1=1k\Omega \ R_2=R_3=1k\Omega## ##C=220nF \ f = 250Hz \ E_0=10V## Homework EquationsThe Attempt at a Solution ##Z_{th} = Z_{R_2}//(Z_c+Z_{R_3}) =...
  15. Lapse

    What is the Voltage on C1/C2 after the switch closes?

    Homework Statement Homework Equations Vf+(Vi-Vf)e-t/RC Tau = RC The Attempt at a Solution [/B] Normally, I would use the eq'n mentioned above to find Vr in an RC circuit. However, this second capacitor is throwing me off. Is there a new equation I should use? How do I think about this...
  16. Peter Alexander

    Engineering Computing resistance in given circuit with BJT

    Hi, before you proceed with reading this question, I would like you to know what I do not expect anyone to solve this task for me. I have a problem with a single step in the solution and I'm only asking you to help me with this one step. 1. Homework Statement Compute ##R_B## so that Q-point of...
  17. A

    How do I use full-bridge strain gauge circuit to measure F?

    Hey all, I am using a Wheatstone bridge with 4 strain gauges as resistors. I have a formula for the output voltage (Vout). My questions is how do I make it so instead of voltage I measure force? Do I simply apply a set max. force (let's say 140N), see what voltage I get (Vout,max) and then use...
  18. C

    Engineering Input Impedance of a MOSFET circuit

    Homework Statement (From Razavi's Design of Analog CMOS Integrated Circuits - Chapter 6) Homework EquationsThe Attempt at a Solution Not too sure about calculating the input impedance of this. Initially I thought that it would be the series combination of C1 and C2, since we are...
  19. FreeForAll

    Solving a Perplexing Thought Experiment: A DC Electrical Circuit

    This thought experiment has been bugging me for a very long time - I'm hoping someone can help me understand it. Premise: - Simple DC electrical circuit consisting of a battery, wire, light bulb, and another wire to complete the circuit. - Each wire has a length of 1 light-year (yes, very...
  20. bornofflame

    RC circuit - Rate o'energy dissipated = rate o'energy stored

    Homework Statement 1. A 2.01 uFcapacitor that is initially uncharged is connected in series with a 6.51 kΩ resistor and an emf source with 74.6 V and negligible internal resistance. The circuit is completed at t = 0. b) At what value of t is the rate at which electrical energy is being...
  21. Kevin J

    Confusion about this Live & Neutral Circuit Problem

    The left circuit is a simple live&neutral circuit, it is neutral (0V), because it is in fact 'grounded'. If I unplug the wire connection to the ground, makes both wire, live. Now, If I replace the grounding connection with a person, why would he receive the shock, doesn't the man 'neutralize'...
  22. bornofflame

    RC Circuit - Rate energy is dissipated in the resistor

    Homework Statement 1. A 2.01 uFcapacitor that is initially uncharged is connected in series with a 6.51 kΩ resistor and an emf source with 74.6 V and negligible internal resistance. The circuit is completed at t = 0. a) Just after the circuit is completed, what is the rate at which electrical...
  23. Krushnaraj Pandya

    EMF and potential in a circuit

    Homework Statement Four identical cells each having emf E and internal resistance r are connected in series to form a loop abcd as shown in figure (picture 1). Find potential difference across ab and ac. 2. Homework Equations V=IR equations for combination of cells and resistances The...
  24. W

    Engineering Grounding Op-Amp circuit exercise

    Homework Statement 2. Homework Equations 3. The Attempt at a Solution For the first set of questions: I've worked through to part 6), at which is I encountered my first problem. I'm not entirely sure what the question is asking. Is it as if there would be a capacitor between...
  25. Kevin J

    B Is it Possible for a Short Circuit to Contradict Voltage in a Parallel Circuit?

    Assume a superconducting parallel circuit being shorted, a 10V ideal battery, and a 5 Ohms resistor connected on one of its path. This means the shorted path has a 0 Ohm resistance, which also means it has no potential difference, how is this even possible if voltage across in a parallel circuit...
  26. S

    Current through circuit when switch is open

    Homework Statement Seven equal resistors, each of resistance 2Ω are connected with a battery of 3V in a circuit shown. If i1 is the current when the switch S is open and i2 is the current when switch S is closed, find the value of i1/i2. Homework Equations 1)Equivalent resistance formula...
  27. Kevin J

    Why does current choose the short circuit path?

    I've seen answers saying that electricity takes path of least resistance, I know this and there is no need to explain this for me. A forum's answer told me that the electrons initially flow through to the path with resistance and eventually becomes congested (redirecting the remaining electrons...
  28. D

    Did I count this current in a circuit correctly?

    This i a test question and we are not allowed to use a calculator, so I was wondering whether I did everything correctly, since the I1 = - 1/7. I am supposed to find out I3, but stopped at I1, since the result is a bit tricky. 1. Homework Statement R1 = 10 ohm, R2 = 20 ohm, R3 = 40 ohm I3 = ...
  29. O

    Comparing the brightness of each bulb in a circuit

    Homework Statement Four identical light bulbs are connected to a battery as shown in the diagram. Switch S is originally closed. If switch S is opened, what happens to the brightness of each bulb? Homework Equations V=IR The Attempt at a Solution - By opening the switch, no more current...
  30. Shivang kohlii

    Engineering An electric bulb of 500 W at 100v is used in a circuit

    If the circuit has 200 V supply. The resistance R that must be put in series with bulb so that it draws 500 w is? 2. Relevent equations P= v^2/r I = v/r 3. My attempt at the solution R= V^2/P r (bulb)= 10000/500 = 20 ohm Now for 200 v supply .. P= 500 W V= 200V Rnet = 20 + R R+20= 80 R= 60...
  31. P

    Why does switching this circuit on take longer

    Homework Statement In this circuit, switching on is about twice as long as the delay for switching off 2. Homework Equations 3. The Attempt at a Solution When switching this circuit on the inductor will oppose the change of current therefore basically slow down the lighting of bulb B. When...
  32. CMJ96

    A Help Understanding a Quantum Circuit Identity

    Hello I have the following quantum circuit identity for converting a controlled U gate (4x4 matrix) into a series of CNOT gates and single qubit gates $$ U= AXA^{\dagger}X$$ where A is a unitary matrix. Here is a picture of the mentioned identity. Can someone help me understand conceptually...
  33. J

    Circuit with resistor, switch and capacitor

    Homework Statement We have a circuit with a battery, two resistors, a switch and a capacitor. We assume that the battery has a switch so that we can choose whether it should be a voltage source for the circuit. a) At time t = 0, we put on a voltage Vs over the battery in the circuit. What is...
  34. S

    Engineering Solve LC Circuit Problem: Examples & Resources

    Homework Statement An image of the problem is attached. I have to find 2 currents in an LC circuit. Homework Equations V = L(di/dt) The Attempt at a Solution [/B] I have no clue how to do this type of problem. Are there any examples problems similar to this online? Or can someone give me...
  35. F

    Engineering Write the Boolean expression of a given logic circuit

    Homework Statement In the logic circuit shown below , write the Boolean expression for the output function X . Which gate(s) could be removed without affecting the function X ? Homework Equations - The Attempt at a Solution [/B] So , we can get rid of ##A \overline{B} C ## . gate # 4. Right ?
  36. Muhammad Usman

    Pull Up resistor in the Voltage?

    Hi, May be this is the most basic question, but I don't understand the concept of pull up resistor and how they maintain the voltage value. For example let's take an example of below circuit. There is 5 volts battery and then there is 10K resistor which is further connected with the Vout which...
  37. S

    Engineering Op-Amp Resistive Circuit Homework: Finding Vo in a Given Circuit

    Homework Statement The attached picture is the circuit I have been given and I am asked to find Vo (the voltage drop across the 6k resistor. Homework Equations v_out/v_in = (R_1 + R_2)/R_1 V+ = V- The Attempt at a Solution So I know that the voltage drop across the 6k resistor is just the...
  38. C

    Symmetry in Electrical Circuit Analysis

    How is symmetry used to solve electrical circuits? I have seen several problems in books in which currents in two resistors are said to be equal due to 'symmetry'. That is a concept that I fail to understand and thus cannot apply. In class, we were shown a few circuit diagrams which were...
  39. E

    Dispersion equation for an LC Circuit

    Need the dispersion equation for chain consisting of cell units ( LC unit scheme in attachments). I know I need to make complex Kirchhoff equations and after get the dispersion equation but absolutely don't know how to do it. All examples that I find in web very poor including books, articles...
  40. Shaq Melbourne

    Engineering LabVIEW Opamp Circuit Homework Solution with USB6008 Measurements

    Homework Statement The task States to build the I-V characteristic circuit where AIa and AIb are floating source measurements taken with the USB6008 and VS is supplied by the voltage follower circuit. I've also attached the actual script, for added context. Homework EquationsThe Attempt at a...
  41. S

    Equivalent circuit of the waveguide application problem

    Hello! I'm trying to simulate a connection between two 2-port devices via waveguide but calculated results do not agree with those, calculated in simulation software. All calculations are in the notebooks. I took a two-port device and compared its S11 characteristic calculated using equivalent...
  42. A

    How Do I Solve This Combination Circuit?

    Could somebody help me out with this combination circuit? The answer that I get is 62K but that is not one of the answers. At first, I thought the 10kohm and 20kohm wherein series and the other side as well. Then I thought they are all in parallel because of the different current flow they all...
  43. Safder Aree

    Engineering Finding Internal Resistance through Circuit Analysis

    Homework Statement Given this following circuit: What is the internal resistance of the meter movement ( R_I). This is part of a project I'm doing and I know the equation that gives you the internal resistance in this circuit. $$R_I = \frac{R_sR_p}{R_s - R_p}$$. However, I have no idea how...
  44. Lapse

    Engineering Design Circuit to Convert Current to Voltage | LTSpice Also

    Hello, We just finished up midterms and I actually did well--got an A. However, somehow between the midterm (class before last) and last class we jumped to creating a circuit with a diode. I am pretty lost. 1. Homework Statement Homework Equations Voltage / Current = ResistanceThe Attempt...
  45. cnh1995

    How Can Energy Change Instantaneously in a Coupled Circuit?

    Homework Statement Homework Equations Kirchhoff's lawsThe Attempt at a Solution Applying KVL on primary, di1/dt+i1=5+2di2/dt...1) Similarly for secondary, 2di1/dt= 4di2/dt + i2...2) After solving these equations using Laplace Transform, I got I1= 5-e-0.2t A and I2 = 2e-0.2t-2e-0.25t. I...
  46. M

    Hi, how to make 2 IF from one IF amplifier circuit, to get higher gain

    Hi, i take one If amplifier, from internet and i want to make the second the same, but i don't know how to couple, of what i need to do, to get more gaing can somebody help me? here is one IF amplifier in ltspice, rename in asc, or remove only txt extesion. and what is the best to do, is for fm...
  47. G

    Explaining a signal converting circuit

    i have a drawing of a circuit that converts a signal in range [-5,5] V to a range [0,1.2]V . i wish to understand how it works.. i have basic knowledge of electricity as an undergraduate in general physics but a bit rusty , thus i am here looking for answers...
  48. Y

    State Space Model of an RL Circuit

    Homework Statement For the given circuits, identify state variables and derive a state-space model for each. Assume the input is v(t) and the output is vL(t). Homework EquationsThe Attempt at a Solution [/B] So my issue is that I solved this problem using two different methods. First...
  49. K

    Tripping Behavior of Circuit Breakers

    For US residents. If you have the above circuit breaker put in your panel phase to phase (2 pole).. and one of the phase touches neutral.. would the circuit breaker trip or not? It's rated 240 volts.. yet one pole only has 120 volts.. would that 120 volts shorting the neutral trips it? This...
  50. ItsTheSebbe

    Finding the bandwidth of a parallel RLC circuit (+MATLAB)

    Homework Statement The attempt at a solution Constructing the total impedance of the circuit as follows, $$\frac{1}{Z_T}=\frac{1}{Z_R}+\frac{1}{Z_C}+\frac{1}{Z_L}$$ where $Z_R=R$, $Z_C=-j\frac{1}{\omega C}$ and $Z_L=j\omega L$. $$\frac{1}{Z_T}=\frac{1}{R}+j\omega C+\frac{1}{j\omega L}$$...
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