Rc Definition and 643 Threads

Homework Statement Attached. Homework Equations The Attempt at a Solution Attached. I am looking at the circuit at t<0. I need to calculate v(0) but I'm not sure how to apply nodal analysis when you have a capacitor in the circuit. Do capacitors follow ohm's law?

The biggest problem is that I have no knowledge about the math for oscilliscopes. This is a post lab but all we actually did was push a few buttons to record measurements, we did not go into any detail about the methods, just what an oscilliscope was supposed to measure. Homework Statement...

Hi. When trying to derive the equation for voltage across a discharging capacitor in series with a resistor using Kirchhoff's laws, I got stuck. My attempt was that the voltage gain across the capacitor should equal the voltage drop across the resistor, therefore q(t)/C = i(t)*R, or q(t) -...

Homework Statement The figure shows the circuit of a flashing lamp.There is a current through the lamp (see the photo) only when the potential difference across it reaches the breakdown voltage VL; the capacitance DIScharges completely through the lamp. (a)A lamp has breakdown voltage...

Hi~ Actually I am fine with calculating the delay but I haven't got the concept clearly enough. Both nmos and pmos have their equivalent RC models. I understand how the RC model of nmos works when its on or off but I don't get how the pmos turns out this way. When its off, the upper part...

Homework Statement I just want to understand, how to calculate transfer function. Here is simple example: Homework Equations The Attempt at a Solution But in this circuit I don't understand how to do it. I have to find T and k as it is in preview. Which is the element for...

In an RC circuit, the phase angle between the input and output voltages (not current and voltage) seems to be proportional to the amplitude of the output voltage. That is, as the phase angle between input and output goes to plus or minus 90 degrees, the output voltage goes to 0. Why is that?

Homework Statement Ok guys, so this is a slightly long question, but bear with me because I think I figured out most of it. I just need help towards the end. So I have a circuit with a current source in parallel with a capacitor and also in parallel with a resistor (see attached image). This...

Homework Statement http://imgur.com/OowiMCR As noted in the image: In the circuit below, R1=R2=10kΩ, and C=0.1μF. Plot Vout(t) if the input, Vin, is a step function of height V0 at t=0 Homework Equations Vcap=V0-Ce-t/RC The Attempt at a Solution I was hoping someone could...

These are 2 stand alone problems, however the answers disagree with one another and I am trying to reconcile their differences. Any insight would be appreciated! :) The answer is C. The answer provided with this question is that "there is no dependence on resistance of any kind". However the...

Homework Statement Determine the voltage drop across the resistor when the capacitor has been discharging for 10μs. Capacitance=400 pico farad and is charged to 10v through a 50kΩ resistor. Homework Equations Vr= V*e -t/CR The Attempt at a Solution Vr = V-Vc at the instant of 10μs...

Homework Statement Determine the current flowing when the capacitor has been discharging for 5μs Capacitance=400 pico farads which is charged to 10v through a 50kΩ resistor. Homework Equations Vc = ve-t/CR The Attempt at a Solution So Vc =Ve -t/CR -t/CR =...

In lectures I covered how a Schmitt trigger can be used in an RC circuit to determine the capacitance of the capacitor (Where the Schmitt trigger switches at 0.3V+ and 0.6V+). The equation given was that C = 1.2 R \ T (time period) Does anyone know how to derive this or where it comes from...

Dear all, I have problem to find the differential equation for my circuit shown in the attached picture. For input I have a current source, and the output is the voltage U (the voltage between the first and the ground node). I need the ODE to find the mathematical response of the system...

Hello, I am trying to figure out the transfer function for an RC phase shifter: http://imgur.com/2dnRYn7 (Picture of circuit) I am not sure how to calculate the output and specifically the phase of the output of this circuit. I understand that I need to consider one of the 'golden rules'...

Homework Statement Use current equation and find di/dt expression, hence show if initial gradient were maintained the current would be 0 after 1 time constant. Homework Equations I calculated RC to be 0.5s i=0.02e^-t/0.5 The Attempt at a Solution I solved di/dt to be...

Homework Statement Homework Equations w = 1 / sqrt(LC) The Attempt at a Solution hi there, I 1. I decided to choose, 93.3 MHz so 93.3 x 10^6 Hz is my freq. 2. I googled how a band pass filter diagram should look like and I found this, is the only way to create a low...

Homework Statement I'm trying to understand how Twin-T notch filters work. I get that they are made of two passive RC filters, one low-pass and one high-pass in parallel. The trouble I'm having is how to determine the corner frequencies (where Vout = 0.707Vin). The gain of the corner...

Homework Statement A 140μF defibrillator capacitor is charged to 1500 V. When fired through a patient's chest, it loses 95% of its charge in 40 ms. What is the resistance of the patient's chest? Homework Equations The Attempt at a Solution According to "Mastering Physics," the solution that...

Hey PF! I have a test tomorrow and some of the material is on the basics of RL and RC circuits set up as high pass or low pass filters. Does a High pass filter bode plot look the same whether it's RC and RL? Same with a low pass? Can anybody to an online resource of what bode plots look like...

Homework Statement Plot I_r vs. time and Q_c vs. time starting from when the switch is moved from its lower position to its upper position. Label both axes with numbers and units. Show three time constants. Assume that the capacitor is initially uncharged. After the circuit reaches its...

I bought a biophysics book the other day, and immediately began reading it. Sadly, I'm only 12 pages in now, because I seem to have run up against a wall in my understanding. You see, I don't understand a step being taken in the math, and am not sure what I should learn to understand it better...

Homework Statement C1= 2.0 μF C2= 5.0 μF the resistor has a resistance of 0.10 MΩ The circuit shows the charging of a capacitor a) At t=0 the switch is closed. What is the initial measuring on the ammeter? b) After the current has decayed to zero what are the voltages at points A,B and C...

Homework Statement Given V R C for the figure, determine a. The voltage of a with respect to b when the switch is open? b. Which point a or b is at a the higher voltage? c. What is the final voltage of point b with respect to ground when the switch is closed? d. Wow much...

Homework Statement Task is to write differential equation for this circuit. Homework Equations The Attempt at a Solution I'll try to solve the task, but now I want to know, is it possible to use voltage source instead of current source. For example, I can calculate ekvivalent...

Hi, I have been given a question which involves analysis of a series RC circuit. The system in question has a 4Ω resistor in series with a 1000μF Capacitor (the capacitor is to be considered as completely uncharged before t=0). There is a 12V supply in the circuit. At t=0, a switch is...

Homework Statement Signals from sources of different kinds are often very weak and very quick. To minimize the noise risk they're often led through coaxial cables. How long can one [coaxial cable] be if it has the capacitance 80pF / m and resistance 0.04 Ohm/m and you want to transfer noise...

Hi! Homework Statement Homework Equations V = IR Kirchhoff Current and Voltage Law. The Attempt at a Solution I am facing difficulty with this RC circuit. I tried looking up solutions but all I could find were either exclusively series or parallel. My first guess was to take Total Current...

Hi, Basically I have circuit with an input Vi (s) across a capacitor C which is in parallel with a resistor R1. And these 2 components are in series with another resistor R2 (please see attached drawing). The question states: Show that the transfer function of the circuit is: Vo/Vi...

Homework Statement A capacitor C=8.00*10^-8F which has an initial charge q=1.4*10^-6C starts to discharge through a resistor R=3.00*10^6Ω at time t=0. Determine the total energy W dissipated as thermal energy in the resistor. Hint: use energy conservation. The Attempt at a Solution I...

I'm having a hard time understanding and solving problems in moderately complex RC circuits... Please Help. You don't have to solve right up to the numerical value, that is not my priority, Rather If you could just explain how to begin and process through the question, It would be best...

I'm having a hard time understanding and solving problems in moderately complex RC circuits... Please Help. You don't have to solve right up to the numerical value, that is not my priority, Rather If you could just explain how to begin and process through the question, It would be best...

Homework Statement Homework Equations vc(t) = vc(∞) + [vc(0+) - vc(∞)]*e-t/τ (Voltage in a driven RC circuit) τ = RC (time constant for an RC circuit) The Attempt at a Solution I'm pretty shaky with these sorts of problems and am quite unconfident of my work here. Step...

Homework Statement A simple type of blinking light circuit can be constructed using a neon lamp. The circuit has a 4.0uF capacitor in parallel with a neon lamp. When the voltage is low in the RC portion of the circuit, the lamp does not conduct electricity. Therefore, it is effectively not...

Hi guys, I have a quick question I think. Let's consider an RC differentiator driven by a 0-5V square wave which is initially at 0V. When the input voltage suddenly makes the transition to 5V one side of the capacitor will jump to 5V. I've read that the other side (side with the resisitor)...

Hello I have a conceptual question about using Kirchhoff's voltage rule to derive expression of the charge in the RC series circuit when it is being charged by certain EMF. Usually most books start by writing the equation \mathscr{E}-iR-\frac{q}{C}=0 But when the charging is going on...

Building a RC Lancaster 1/10 Scale Planning on putting in 4 x 4stroke glow fuel enjins on it Expected weight is 10-20 kg - but have no real idea yet Any sugestions? Real Lanc is as follows - from Wikipedia of coarse Wingspan: 102*ft 0 in (31.09*m) Height: 20*ft 6 in (6.25*m) Wing...

Homework Statement Can a series RC circuit and a parallel RL circuit have the same impedance if the R is the same in both? What would the values of R, L and C have to be if they can? Why/why not, physically speaking? Homework Equations Zr=R Zc=1/iwC ZL=iwLThe Attempt at a Solution I know in...

Homework Statement A simple RC circuit with an EMF source ε, Resistor R and capacitor C are in series. When the switch is closed find the rate of energy stored in the capacitor, the power dissipated in the resistor, and the power supplied by the emf as functions of time. Homework Equations...

Homework Statement For the multi-loop circuit as shown, assuming the capacitor is initially uncharged, find the currents in each of the resistors at t=0 after the switches are closed. So I believe there are 8 unknowns really because of the 8th branch with the capacitor. If you look at the...

Homework Statement Switch is initially opened with the capacitor uncharged. At t=0 the switch is clsoed. At time=t1 later, the potential difference between A and B is 2.00volts Find the charge on the capacitor at time t1. R=10,000ohms C=2.4nF Vb=12volts VA->B-=2.00volts Homework...

Homework Statement "A capacitor is being charged from a battery and through a resistor of 20kΩ. It is observed that the voltage on the capacitor rises from 10% of its final value to 90%, in 15 seconds. Calculate the capacitor's capacitance. t = 15s R = 20kΩ Vi = 10% of max Vf = 90% of max...

Homework Statement How much time does an RC circuit require to become fully charged assuming that the capacitor was initially uncharged. resistance = R capacitance = C Voltage = V Homework Equations Q=CV(1-e^(-t/RC)The Attempt at a Solution so T = -ln(Q/(CV) - 1)RC but Q = 0 since it's...

Homework Statement A 10-µF capacitor is charged by a 10-V battery through a resistance R. The capacitor reaches a potential difference of 4 V in a period of 3 s after the charging began. Find the value of R.Homework Equations c=q/v q=CE(1-e^-t/RC) i=(E/R)e^(-t/RC)The Attempt at a Solution I...

Homework Statement Uploaded problem 5 Homework Equations i1=(R2/(R1+R2)) i2=(R1/(R1+R2)) The Attempt at a Solution Are my answers for problem 5 ok?

Hello, I know that if two resistors are in parallel or two capacitors, they have the same voltage. However, is it the case that a resistor and capacitor in parallel also have equal voltage?

Hello, At the moment, I am writing the theory portion of my lab report. In the RC circuit, will the electric potential across the capacitor be at the same electric potential as the battery? Or will it depend on the voltage drop across the intermediate resistor?

Homework Statement http://img163.imageshack.us/img163/6339/rccircuit.png Homework Equations The Attempt at a Solution I'm trying to find the node voltage. I was going to try and solve the problem knowing that the net charge is zero. Q = CV I'm having problems the voltage...

Thanks, solved!

Hello, This is my first post so I hope I do everything correctly. I am required to calculate the RC time constant in piezoelectrics. I am trying to do this with data that I already have, Resistivity (not resistance) and Permittivity, and I no longer have the dimensions of the sample that I...