Circuits Definition and 1000 Threads

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...

Homework Statement http://imgur.com/a/qlQ5z Homework Equations i=i(o)+1/L integration(v0) dt formula is in the attemp at a solution. The Attempt at a Solution http://imgur.com/a/HVjl1 For the interval 2<t<infinite . I understand...

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...

Homework Statement http://imgur.com/tQR7Jdt Homework Equations xc= vm/im The Attempt at a Solution http://imgur.com/a/RwIUA Can someone please explain where did they get that pi/2 ? did they integrate 2cos(10t)or something? Thanks

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...

Is it possible to have a purely parallel magnetic circuit in any case?(it should not be a series or series-parallel circuit)

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...

Hi everyone. I am tasked with amplifying an input voltage of around 1nA at anywhere between 10,000kHz to 1MHz to a sufficient amount. We've been using op-amps in multiple stages in series to amplify the signal. At our disposal we have a function generator, oscilloscope, breadboard and...

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! :)

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

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 kirchhoffs voltage law which says that the voltage drops around both paths must be equal...

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...

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...

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?

What is the latest technology update on making circuits aware of being aware.. this is to enable understanding of how our neutral circuits are aware of being aware.. what is the most accepted theory about this? Is it Re-entrant loops in the brain?

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...

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...

Hi Everyone, I will try to keep this short as I can and to the point, there is a bit of a back story, so bear with me. For the last 18 months (on and off as life allows), I have been trying to develop an induction heating assisted machine for 2 reasons. 1 - To learn as much as I can by doing...

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...

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...

Hi All... I'm in the process of restoring an old Eddystone 730-1a receiver (all valves for you younger folk) and the service manual gives the test point voltages based on a 20k/Volt meter. I realize that some, if not all of these voltages are relative to a high impedance source and the 20k/V...

Homework Statement Exercise 4.15 on the image. The exercise asks for the value of the current I using superposition Homework Equations Superposition theorem, nodal and mesh analysis The Attempt at a Solution I think i am doing the mesh analysis wrong, but can't see where. Can someone...

Homework Statement The problemas statement is: "Find Vo and Io by the superposition principle" Homework Equations Nodal Analysis and The Superposition Theorem. The Attempt at a Solution So, I tried to shutdown first the independent 30V tension font. It led me to Vo = 8V. Then, turning off...

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...

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...

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...

Homework Statement A battery with an emf of 60 V and an internal resistance (r) is connected to a 10 ohm external resistance. The power lost inside the battery is 50w. The same battery is then connected to a 4.0 ohm resistance. The power loss is 200w. What is the internal resistance of the...

Say I had a 10VDC supply and I need around 3.3VDC at 30ma. Let's say the 3.3VDC will power a LED. V1= 10VDC R1= 82 ohms R2= 47 ohms V2= 3.64 VDC from the junction to ground I= 28.24ma...I guess I don't know what effect the LED will have on the circuit and I don't understand how to find the...

Hi Does anybody have any useful material on how to calculate unknown voltages in an amplifier circuit. Thanks in advance.

Hi, I'm trying to wire a transformer which steps my mains voltage (240VAC) down. I just finished wiring the the primary to the plug, and thought I should test my connections by plugging it in. The coil was not inside the core or near the secondary, it was just lying on a piece of paper. I...

The goal of this problem is to find the equivalent resistance of all the resistors. Each resistor shown in the image has a conductance of 1 mS which I believe is equal to 1000 ohms. I attached a picture of the circuit diagram in which I show some of my work in order to convey my erroneous...

Hiya, this is my first time posting so apologies for any errors in formatting. :oldsmile: I am confused as to whether when Thevenising a portion of a circuit is it to simplify BUT provide the same output characteristics, meaning the workings of the Thevenin part of the circuit may behave...

Can someone please help me out with this practice test and provide explanations?

I don't understand why the voltage drops only when the charges in an electric circuitnpass through resistors or electric devices, but don't drop as charges move through the wire. As charges move through the wire due to electric potential differences, from a high potential to a low potential...

I was wondering, at high frequency circuits, when the lumped circuit model must be used, why does impedance depends on the position in the wire? By the way, it's my very first post here =D

I've searched around and all I can find are people quoting the equations. I see it in the math, but it seems contradictory. Here is my line of thought: 1. A source maintains a voltage difference across its terminals. 2. The difference in voltage causes charge to flow from higher to lower...

Homework Statement Homework Equations equations listed below in chart The Attempt at a Solution here is my answer, i just need to know if I am doing this correctly, thanks :)[/B]

When attempting to find an answer to the "quality" of sound one attains from various audio cables, most of the research leads to the very subjective answers of audio/sound engineers. I was hoping to gain some insight from a physics/engineering perspective. I'm curious if an expensive or...

Homework Statement This isn't so much of a problem itself but I found it interesting that on the All About Circuits website, two of the questions give a phase angle for impedance as opposite the angle of current. I understand the current is 90 degrees out of phase with voltage in both RL and RC...

Homework Statement {image inserted in-line by mentor} http://imgur.com/lnURBGX Calculate the magnitude of the current through point Y. Homework Equations Ohm's Law: V=IR Kirchoff's Junction: 1/Req=1/R+1/R2+1/R3+... The Attempt at a Solution I have been told that in parallel circuits the...

Homework Statement Hi, I am having some trouble with DC circuits, especially those that include a combination of series and parallel circuits (networks). There are a couple of problems that I have worked through, but have no idea if I am on the right track and have the correct answers. My work...

I've been studying circuits, but I can't find any resources that really answer my specific questions. So far I understand that a battery creates a potential difference between the two terminals, one of which is positive while the other is negative. There is a buildup of positive charge on the...

Homework Statement For the characteristic curves shown below, select resistors for an H-biased common emitter amplifier for symmetric operation. Show the load line and operating pointing on the graph Homework Equations What does it mean by "symmetric operation"? The Attempt at a Solution...

Hi, I need to learn how to find equivalent circuits using what my textbook calls open circuit and short circuit methods. Thank you all for you support

I do not understand these two equations V[eq][/SUB] = V[in][/SUB] and R[eq][/SUB] = -(V[oc][/SUB] / I[oc][/SUB] ) Your help is much appreciated

Homework Statement A parallel combination of 0.1M Ω resistor and a 10 μF capacitor is connected across a 1.5 V source of negligible resistance. The time (in seconds) required for the capacitor to get charged upto 0.75 V is approximately (A) ∞ (B) ln 2 (C) log 2 (D) Zero Homework Equations...

Homework Statement In the following figure(Figure 1) switch S1 is closed while switch S2 is kept open. The inductance is L = 0.360 H, the resistance is R = 31.0 Ω , and the emf of the battery is 22.0 V . At time t after S1 is closed, the current in the circuit is increasing at a rate of di/dt =...

Homework Statement [/B] Three resistors are connected to a real battery. The open circuit voltage of the battery is 4.5 Volts. The voltage across the 5 Ohm resistor is 2.5 Volts. A) What is the voltage across battery terminals? B) What is the internal resistance of the battery? Here's a...

at electric circuits , at RLC circuits , in case resonance :why do we calculate the frequencies w1 & w2 at half power frequencies ?

Hi! I have a real problem in understanding the use of symmetry for finding equal potential points in nasty electric circuits. There are lots of problems were the solution simply says: "due to symmetry reasons, nodes X and Y have equal potential", but I rarely really understand the so called...