1. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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  (b) Find values for VA and VB.  (c) By calculating the currents supplied by the 44 V and 2 V sources, or by any other means, calculate the total power...
9. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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...