Read about circuits | 151 Discussions | Page 3

  1. V

    Circuit with two voltage sources, finding voltage at nodes

    Okay, so why is it that Vc assumed to be 12v - 0.7v (D1), how about contribution from the 9v battery?? Why is this not affecting the voltage at node C? Why Vc isn't 9v - 0.7v (D2) = 8.3v?
  2. Jayalk97

    Summing op amp circuit help?

    Homework Statement Solving for this circuit here, where V = -5V Homework Equations The Attempt at a Solution I found the equation for a summing op amp like this one, plugged everything in and ended up with -3V, which is marked wrong. I'm really at my wit's end here and the homework has been...
  3. Bassa

    Initial Voltage in an RC circuit with a Current Source and no Voltage Source

    Homework Statement [/B] Derive an expression for vc(t) in the circuit of Figure P4.13 and sketch vc(t) to scale versus. I attached a screen shot of the circuit for this problem. time. Homework Equations V = IR V = V0exp(-t/tau) The Attempt at a Solution [/B] I am trying to find the...
  4. Asmaa Mohammad

    The current in RLC circuit.

    Homework Statement In the tuned circuit below, what will happen to the reading of the ammeter when: a) source frequency increases. The voltage is constant b) the capacitance increases. The voltage and source frequency are constant c) The voltage increases. Source frequency is constant...
  5. solour

    Current Through A Resistor That Is In Parallel With A Capacitor

    Homework Statement [/B] My question is regarding part C of the question. Homework Equations V = IR V(t) = V(1-e^(-t/tau)) The Attempt at a Solution My idea is to use Kirchoff's Voltage Law and find the voltage of the capacitor as a function of time, then since the voltage across capacitor is...
  6. fuvest

    Electrical Circuit Problem / Electric Potential Difference

    Homework Statement In the following picture, the absolute value of the difference in electric potential, between points A and B is: A)5V B)4V C)3V D)1V E)0V Homework Equations E =qV V = iR The Attempt at a Solution I have no idea where to start on this one, just started my electric...
  7. doktorwho

    Engineering Best books on solving circuits

    Hi, do you have any recommendations of books that deal with circuit analysis and circuit solving? I'm currently involved in a course that deals with linear circuits, and we are learning all of these methods of loop currents, thevenin's and norton's theorem, potential of knots and lots of methods...
  8. W

    Engineering Find total power in a circuit with two power supplies

    Homework Statement (a) Apply Nodal Analysis, writing down the equations which determine VA and VB, the voltages at nodes A and B [8] (b) Find values for VA and VB. [4] (c) By calculating the currents supplied by the 44 V and 2 V sources, or by any other means, calculate the total power...
  9. A

    RLC circuits problem

    Homework Statement A certain circuit has a resistance of 30 Ω, inductance of 5.0 mH, and capacitance of 0.375 µF. At time t=0, the capacitor is charged with 4.0 µC on the top plate (and -4.0 µC on the bottom), and the switch is then thrown so that the capacitor can discharge through the...
  10. doktorwho

    Can you help me solve this Boolean algebra problem?

    Homework Statement Prove that $$(\bar{a} + b)(b+c) + a\bar{b}$$ where ##a,b## can be from the set ##B\in\{0, 1\}## equals $$a+b+c$$ Homework Equations Rules of Boolean Algebra 3. The Attempt at a Solution [/B] My attempt: ##\bar{a}b + \bar{a}c + bb + bc + a\bar{b}## ##b(\bar{a} + 1+c) +...
  11. M

    Lab: Plot graph of resistance, R (in Ohms) versus 1/d^2

    Homework Statement We were given five samples of nichrome wire, each with a different diameter but the same length. A micrometer was used to measure the diameters. We then measured and recorded the electrical resistance, R in Ohms of each nichrome sample with a DMM. I will try to summarize all...
  12. C

    A circuit with multiple sources of voltage

    Homework Statement Solve this circuit: a) Mark all currents b) Write a system of equations allowing you to solve for the currents 2. The attempt at a solution Part a) in attachment. Part b) \epsilon_1 = i_1 r_1 + (i_1 + i_2 + i_3) R \epsilon_2 = i_2 r_2 + (i_1 + i_2 + i_3) R \epsilon_3...
  13. M

    Engineering Circuits with Resistors

    Homework Statement https://s10.postimg.org/lb6n94ua1/20161007_190700.jpg Homework Equations V=IR The Attempt at a Solution So far I haven't had any problems finding the Req. However, I am having trouble with the VIR chart. Can anyone confirm whether or not I did it correctly. My thought...
  14. Blockade

    Trouble w/ setting up the equations for capacitive circuits

    Homework Statement Homework Equations .Q = CVab The Attempt at a Solution I am having a hard time understanding when to put the capacitance in the denominator. I get that Voltage = Charge/Capacitance, but for the equation circled in red "q1/c + q2/c = q3c" ... I don't get why each of...
  15. RoboNerd

    Theory in approaching Faraday law/circuit question

    Homework Statement I have a square conducting loop of size L that contains two identical lightbulbs 1 and 2. The magnetic field that goes into the page varies B(t) = a*t + b. Lightbulbs have resistance of R0 Here is a question and the sample response. Disregard the part of the question that...
  16. K

    RMS Current through RLC combination ciruit

    Homework Statement Referencing the attached picture: a) Show that the RMS current in the 1 kΩ resistor is 6.5mA. b) If the AC voltage source was replaced by a battery, what would the current in the resistor be? Homework Equations V = IR Z = √(R^2 + X^2) The Attempt at a Solution To begin, I...
  17. AilingLore21

    Are the computed values in Load regulation correct?

    Homework Statement The whole image is at here http://imgur.com/a/Dcbvv , but I will try to elaborate more. I have a 12V fixed source with an RS of 220 Ohms with a 1N4733 zener diode model connected and a varying load parallel to the diode. Find the Source Current, Z current, Voltage at R1, and...
  18. A

    B Battery discharge experiment

    Hi guys! For a school experiment we are supposed to connect a 9v battery to a 180 ohm resistor and multimeter and calculate how long it take to die at different temperatures . does anyone know how can i do this using a formula? I will need it in my report. Thanks for the help! :)
  19. anorlunda

    Insights Ohm's Law Mellow - Comments

    anorlunda submitted a new PF Insights post Ohm's Law Mellow Continue reading the Original PF Insights Post.
  20. RoboNerd

    Lightbulbs and a battery circuit

    Homework Statement Homework Equations no equations The Attempt at a Solution I know that we will have an equal current flowing through bulbs 1 and 2 when we connect them in parallel in accordance with kirchoff's voltage law which says that the voltage drops around both paths must be equal...
  21. N

    Finding voltages

    Homework Statement http://imgur.com/a/L82gU [Mod note: Inserted image inline for convenience] Homework Equations KVL, KCL The Attempt at a Solution [/B] one of my equations will be at one of the nodes and will include all 3 currents. i can also draw two loops, one for the upper triangle...
  22. T

    RC circuit, finding voltage across a capacitor

    Homework Statement I am trying to find the capacitor voltage in the following picture: Find i(t) in the figure below. Assume dc steady state conditions are valid for t<=0. Homework Equations i=c(dv/dt) KCL The Attempt at a Solution At t<0 I found Vc to be 8 volts which should be correct...
  23. Kfir Dolev

    I Is it possible to build a phase shifter from RLC components?

    Say you have a circuit component with impedence Z(\omega). Is it possible combine it in some way to resistors, capacitors, and inductors, so as to shift the phase of the impedance by a constant?
  24. Narayanan KR

    I Poynting energy flow in Eath's atmosphere?

    1.There is an electric field between ionosphere and ground, also earth's magnetic field is perpendicular to this E field, hence by poynting theorem integrating E x H across the entire surface of earth gives a great deal of energy flowing west to east. 2. |S| = (E X B)/u0 = (150 V/m X...
  25. jley18

    I bet my friend I could design a circuit with no background

    Hey everyone! This is my first post here so take it easy on me! Before I get into the circuit I'll give a little backstory here. I'm a business student at a US college right now and I have a good friend who is a Biomedical engineering student. We were arguing about whether or not I would be...
  26. J

    Recharging a battery when Lightbulb and TV are in parallel

    Homework Statement In a household, the wife reads a book that uses a light bulb that has a resistance of 100Ω and is connected to a 100 V line while the husband watches a TV that draws 100 W of power. They do these actives for 200 mins. Power comes from a wind generator that charges batteries...
  27. YellowBelliedMarmot

    AC Power and Effective Currents

    Homework Statement I added a circuit that I drew in microsoft paint to add a visual. Sorry for its ugliness! ;D Homework Equations V = I*Z Ieff = I / sqrt(2) Qreactive = V^2 / Z Pavg = (power factor) * (Veff) * (Ieff) Sapparent = ((Ieff)*(Veff))/2 The Attempt at a Solution Since this is...
  28. YellowBelliedMarmot

    Engineering Thevenin Equivalent of AC RLC Circuit w/ Dependent Voltage

    Homework Statement Find Vth and Zth. frequency = 2kHz Homework Equations w = 2 * (pi) * f ZL = j w L ZC = -j / (w * C) V = I*Z ZR = R The Attempt at a Solution At first I tried using nodal analysis which I receive the value V = 0 v. I believe this is because this circuit only has dependent...
  29. YellowBelliedMarmot

    Engineering Finding the Current Source of an RLC AC Circuit

    Homework Statement Homework Equations V=IZ[/B] Zc = 1/(-jwc) Zl = jwc w = 2(pi)*f The Attempt at a Solution I'm teaching myself circuit analysis, and it's been rough. Ultimately, I been able to mostly figure everything out, but I've ran into a wall with AC. The main problem I am having...
  30. A

    I Help with Experiment on Batteries

    Hi guys!! I am currently having Physics Internal Assessment in my school and I want to do an experiment to calculate the different times it takes for a 9V cell to to discharge (reach a 0.1V) in different temperatures. The problem I am having right now is to efficiently discharge my cell. How can...
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