# Read about circuits | 151 Discussions | Page 2

1. ### FInding current in parallel and series circuits

Homework Statement a. What is the net resistance in the circuit? b. What is the current through the 4 Ω resistor? c. What is the voltage drop across the 3 Ω resistor? Homework Equations R12 = R1 +R2 R34 =R3 + R4 1/Rt = 1/R12 + 1/R34 I3=I4 The Attempt at a Solution a) R12 = 2+ 3...
2. ### B 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"...
3. ### 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...
4. ### Internal Resistance of a Car Battery

Homework Statement An automobile battery has a terminal voltage of 12.8 V with no load. When the starting motor (which draws 90A) is running, the terminal voltage drops to 11.0 V. What is the internal resistance of the battery? Homework Equations V= EMF- Ir The Attempt at a Solution I think...
5. ### I Please suggest whether I should use delta or dx method.

I previously made a derivation of Neumann potential. It can be found in the pdf file below. I originally made it in the ##dx## method. It involved equations like ##dm=I dS##. My maths teacher told that such an expression has no meaning, at least in elementary calculus. However I argued that my...
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### Question about output voltages and impedances

Homework Statement 1. For the first measurement, a load resistance Rload = 119Ohms results in an output voltage V(OUT) = 11Volts. For the second measurement, Rload = 11Ohms results in an output voltage V(OUT) = 3.2Volts. From these two measurements, determine the output voltage V(OUT) when...
7. ### PWM and it`s duration (picosecond pulse widths)

Hello, I wanted to ask, if anyone knows of a realistic circuit, which could be capable of producing a PWM of 1 pico second on and 350 ps off. Thanks to everyone taking the time to answer in advance.
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### Engineering Simulation of Circuits Without Kirchhoff's Laws?

1. The problem statement, all variables, and given/known data I am currently drafting a proposal for a project in Computational Physics. I'm planning on creating a program that simulates circuits numerically instead of solving the system of equations. The purpose of my project is to observe the...
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### Checking my answer... finding the power of a current and a voltage source

Homework Statement The current source and voltage source in the circuit shown in the Figure below are connected in parallel so that they both have the same voltage, vs. The current source and voltage source are also connected in series so that they both have the same current, is. Suppose that...
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### Resistance in circuits

Homework Statement 1) what is the total resistance of this circuit between points A and B? 2) if the horizontal resistor was replaced with an ammeter what would it read if a 6V battery was placed between points A and B? let R = 20 ohms Homework Equations The Attempt at a Solution had...
11. ### Engineering DC circuit analysis: conceptual mistake?

Homework Statement Homework Equations[/B] I have a circuit that consists on 3 components in parallel: a current source Ia, a resistor R and a capacitor C. Ia is directed upwards, while the currents through the capacitor and the resistor are both directed downwards. Select the correct option in...
12. ### Engineering Open-circuit voltage in Thévenin equivalent

Homework Statement Determine the Thévenin equivalent of the following circuit with respect to terminals A-B Homework Equations \$\$U=RI\$\$ The sum of the currents in a node is zero. The sum of voltages in a mesh is zero. I'm always considering the currents in the resistors directed downwards...
13. ### The validity of the interconnection of ideal sources

Homework Statement Sorry in advance for such a basic question, just starting my first electrical engineering course. The question asks if the interconnection of ideal sources is valid. The next part of the question asks us to verify that the total power developed in the circuit equals the...
14. ### Engineering Voltages and current in a circuit: incorrect signal?

Homework Statement Consider the circuit in the figure and calculate V1, V2 and IA. Notice that the symbols V and A represent, respectively, an ideal voltmeter and an ideal ammeter. Homework Equations Ohm's Law \$\$V=RI\$\$ KVL The sum of the voltages of a mesh in a circuit equals zero. We...
15. ### Electric cars -- Does periodic coasting help efficiency?

Hi. I'm a student of electrical engineering, and I've always been interested in the idea of electrical cars, so I came up with a question: let's suppose we want to have a normal trip with car, and then we're not interested in going so fast with it. When we are driving in this condition, it isn't...
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### D-flip-flop circuit

So I have been watching his videos trying to get ready for second year engineering (electrical). However, I am very confused as to what exactly is going on when he is pressing the enable/pulse switch during the run-through at 14:45. He has the enable connected to a capacitor, and he calculates...
17. ### Will there be a difference between the readings of V1 and V2

I= Current flowing V1= Voltmeter 1 V2= Voltmeter 2 My question is that if there would be any difference between the readings of V1 and V2? We know that: By Ohm's law: V= I.R also: Combined resistance of R1 and R2 will be: 1/RCombined Resistance of R1 and R2= 1/R1+1/R2 The reading in V2...
18. ### How would you solve the following cuircut problem?

Homework Statement You are tasked with designing an electrical circuit with a motor, a battery, and several 1ohm and 2ohm resistors. The motor is designed to run at a current of 20A and a voltage of 10V, but your battery supplies 15 V. The motor can then lift a 4kg mass 2.25 meters in...
19. ### Final charge on capacitor for an RC circuit

Homework Statement Homework Equations ##q = CE(1 - e^{-t/RC})## The Attempt at a Solution I assumed that, since the problem specifies that sufficient time has passed, it meant to say that enough time passed. thus making the exponential term in the equation go down to 0, and the charge in the...
20. ### The voltage across an AC source and a resistance in series

Homework Statement In the circuit below, the RMS of the AC source is 100V, the inductive reactance is 50 ohm, the capacitive reactance is 200 ohm, the resistance is 40 ohm and the current flows in the circuit is 0.644 A. Determine the reading of the voltmeter. Homework Equations The...
21. ### Error message in PSpice

Homework Statement Run a transient simulation and plot the three outputs, Vo(t), on the same plot. Use the following settings: 1. Set the Run Time (or Stop Time) so that you plot 3 cycles of Vo(t). 2. Set the Maximum Step Size so that you get at least 100 points per period for Vo(t). 3. Set...
22. ### (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...
23. ### Why does this bulb get brighter after the switch is closed

Homework Statement Homework Equations None The Attempt at a Solution The answer is B, bulb B will be brighter than before. My thought was that initially, the current gets split so that 2/3 I0 goes to the branch with 2 bulbs, since it has twice the resistance of the first branch, and that...
24. ### Potential difference between two points

Homework Statement Question from OCR A Level Physics Exam 2014 (i) and (ii) = definitions (iii) = explanation (iv) = P.d. at 6Ohm Resistor = 0.48V (v) Suggest why the p.d. between X and Z is zero Homework Equations I don't think there are any The Attempt at a Solution I couldn't...
25. ### 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.
26. ### What happens to a coil of wire as current is increased?

Homework Statement Homework Equations L = (N * F_b) / I (where F_b is the magnetic flux) emf = -L * (dI/dt) The Attempt at a Solution I originally thought that the inductance would decrease since it is inversely proportional to current. But, looking at the equation for emf, that would...
27. ### Simple inductance question: Finding steady state current

Homework Statement Homework Equations I = E / R_total The Attempt at a Solution I mostly just want to clarify that my thinking is correct. The solution for this problem shows that the current is split evenly between the two paths. Is that because we're assuming that the inductor has no...
28. ### 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"...
29. ### Diode - Resistor Combination

Helo, I am in an electronic course and we just started studying diodes. I am stuck on the following problem: Place a 100 ohm resistance in series with a diode, and plot current versus voltage across the series combination. I am also given the following values for the diode: n = 1, Is =...
30. ### Tiny Tweak in Teaching Basic Circuits

I'm sure we have all seen the frequent questions from students who don't understand the difference between potential and voltage in a circuit. They seem to think that zero voltage has physical significance. Even using the phrase "voltage drop" is not suffienct, because they say, "What happens...