Rc circuits Definition and 89 Threads

Homework Statement Maximum current: I max = 4.62 * 10^-4 A Time constant of circuit: T = 3.9 secondsHomework Equations T= RC The Attempt at a Solution I'm trying to find the current after 1 time constant. Seems simple enough, the current changes by 63%. So (Imax)-(Imax * 0.63) or...

Homework Statement The RC circuit pictured below begins with capacitor C completely uncharged. I: What is the current at point A immediately after the switch closes? II:What is the current at point A 'at the end of the quaternary period' (I lol'd when he worded it like that) after the switch...

Homework Statement Switch S in the figure below is closed at time t = 0, to begin charging an initially uncharged capacitor of capacitance C = 13.0 µF through a resistor of resistance R = 24.0 . At what time is the electric potential across the capacitor equal to that across the resistor...

Homework Statement I attached the problem I don't understand why the 3 resistors at the top end up being in series for part b. can someone explain that to me. Homework Equations The Attempt at a Solution

Does anyone know of any instance where the the time constants of two RC circuits in series is additive. It seems that when R1=R2 and tao1~tao2 this holds?

Resistor Capacitance Circuits.Say there is a resistor before a capacitor connected in a wired circuit; and there is a battery as the emf source (10V for example). How can the capacitor be charged to approx. the voltage of the battery if the voltage drop across the resistor = the voltage of...

We are studying RC circuits in my physics class and I'm just curious as to what they are even for? My instructor challenged us to go find 5 uses for RC circuits and I am stumped. I can't even find any on google. Anybody know of any?

In the RC circuit shown, the resistance R, the Capacitance C, and the emf of the battery are all given quantities. The battery does not have internal resistance and the capacitor is fully charged after the switch is closed. Prove analytically that, regardless the values of R and C, exactly 50%...

Hey there! First post, been browsing through the forums for a little and I have found problems like this, but I still am getting the wrong answer when I try and do the things suggested. Circuit is simple, and in series. Vs = 23 V R1 = 87 Ohms C=6.1 microfarads with a switch, of course...

Hi, got a naive question (not in the electronics area) I have got two capacitors in series when being charged with a DC (I presume the resistors have negligible conductances so I assume the time constant of charging would follow that of a series capacitor circuit), like this, ---||--- (C1)...

In an RC circuit shown below, with the switch closed after a long time, when the capacitor is charging, there is a current across the capacitor given by Initial current x e ^ (-t/RC)... Is this current...the current supplied by capacitor to the rest of circuit, or simply the current across...

I've been trying to answer the following equation but I just can't get my head around it! 'calculate the time taken 't' for the voltage over capacitor array (Vc) to reach 80% of Vo, in terms of Vo, R, C1 and C2 (caps are in parallel)' I know I need these two equations but I just don't...

I was trying to figure out the relation between the equation of a discharging capacitor and the Natural Inverse Exponent function v(t) = Vo*e^(-t/rc) A*e(-Ct)+B I get that A represents the voltage and the C is the inverse of the time constant but i can't figure out what the B stands for

1. Homework Statement Find the voltage across a capacitor in an RC Circuit, using [V]_{}[/c] (0) = 1, [V]_{}[/i] n(t)=t. 2. Homework Equations dV/dt = (1/RC)(V)=(1/RC)([V]_{}[/in]) 3. The Attempt at a Solution New to this site: I honestly don't know where to start. Done well in...

Homework Statement Find the voltage across a capacitor in an RC Circuit, using [V]_{}[/c] (0) = 1, [V]_{}[/i] n(t)=t. Homework Equations dV/dt = (1/RC)(V)=(1/RC)([V]_{}[/in]) The Attempt at a Solution New to this site: I honestly don't know where to start. Done well in Calculus...

Homework Statement Find the current I1 in the 1.2 resistor at the bottom of the circuit between the two power supplies. Answer in units of A. 015 (part 2 of 3) 10.0 points Determine I2. Answer in units of A. 016 (part 3 of 3) 10.0 points Determine I3. Answer in units of A...

Homework Statement i need to find the Vs(t) and Vc(t) http://img32.imageshack.us/img32/9071/circuiten.jpg The Attempt at a Solution since there is a switch i used two cases to find the Vc one with switch on and switch off switch on...

Homework Statement ok erm, i know how to get the equation V = EMF (1 - e^(-t/RC)) in a RC circuit but what if i had to take into account the internal resistance r of the voltmeter measuring the voltage across the capacitor? meaning now, the circuit contains a resistor R in series with, an...

This is for question 7.53b) . I understand that the inductor acts like a short circuit but how is the current through the inductor affected? Wont the current source (6 A) split at the node before the 4 ohm resistor and before going into the 2 ohm resistor? Also to get the Equivalent Resistor...

The circuit of Figure P.72 has been turned on for a long time, so that you can ignore the transient behavior of the capacitor. Voltage of Battery V = 31 V (e) What is the potential difference across the capacitor C (C = 9 µF)? I thought about using Kirchoff Voltage Law, but I also though that...

I made graphs of simple RC and RL circuits. We were told to mark off at 10% of the rise and 10% away from the max. This gives a delta. We were then supposed to use this information form the graph to calculate tau, and compare it with the theoretical value. I know how to calculate the...

Hello very body i got confused understanding how we can get the derivative of V(t) equal to Hv(t) : V= (1/R) e^(-t/RC) U(t) its derivative V' = Hv(t) = -(1/R²C)e^(-T/RC) U(t) +(1/R)&(t) where : U(t) is the unite step fonction and &(t) is the delta fonction please some help thanks for...

can anyone show me the derivation of an expression for current in a series RC circuit with an AC source? I have seen many for DC sources simply using KVL is it the same for AC? I would imagine that a two part solution is required: 1) homogeneous solution 2)using undetermined coefficients as...

Hey Everyone, I have a question regarding physics. Say you're given an RC circuit with two identical capictors and two identical resistors and that the two resistors are connected in parallel and the two capacitors are connected in parallel and both are used in the circuit. How can you...

In RC circuit, what is the mathematic relationship between the time of charge or dischare and the capacitors ? time of charge or discharge andn the resistances? I know that as the capacitor or the resistance is increased, the time it take to charge is also increase as well. But I am not sure...

Strictly speaking, the equation q=Q_0e^{-t/RC} implies that an infinite amount of time is required to discharge a capacitor completely. Yet for practical purposes, a capacitor may be considered to be fully discharged after a finite length of time. To be specific, consider a capacitor with...

[SOLVED] Help with RC circuits Can someone explain how to find the intantaneous value of voltage in a capacitor at any specific instant in time. I am taking a course in electronics and the textbook isn't really clear on this. I have the equation: -t/T Vc=E(1-e )...

[SOLVED] RC Circuits Homework Statement 1. I have two questions in regards to RC circuits, the first one is how to calculate the maximum voltage across a capacitor, knowing the charge on a battery and the capacitance. 2. The other question involves this circuit where the potential...

Why does a constant current source need to be used in a parallel RC circuit? Why does a Constant Voltage source need to be used in a Series RC circuit?

RC Circuits! A capacitor in a single-loop RC circuit is charged to 63 % of its final voltage in 1.5 s. Find (a) the time constant for the circuit and (b) the percentage of the circuit's final voltage after 3.5 s. Given that V/Vo = 63%, t = 1.5 sec , Time constant =τ Now...

Homework Statement There is an RC circuit with a 6 V battery, a 100 Ohm resistor, and 2.0 microFarad capacitor. At time t = 0, the switch is closed. While this happens, an ammeter measures the current through the resistor. At t = 0.000139 s the ammeter finds that 0.030 A is flowing through...

I get very confused when you have circuits involving Capacitors and Resistors Especially the concept of current traveling through the path of least resistance 1) Let's say you have a circuit with a battery... with a resistor in parallel first, then a capacitor in parallel to the...

Homework Statement In an RC circuit, should a graph of R vs. tau necessarily go through the origin? What does a non-zero intercept indicate? Homework Equations The Attempt at a Solution My graphs look like they go through the origin, and from the equation tau = RC, I would...

I'm working on an RC circuit lab and I can't figure out if my graph of R vs. tau is supposed to go through the origin. According to the equation tau = RC, it seems like the graph definitely should pass through the origin. However, given the definition of tau as the time constant equal to the...

While working on an example in my Circuit Analysis textbook, I came upon the following circuit: A 9v battery is connected to a resistor R1 (this is the left loop of the circuit). It is also connected to a resistor R2 and a capacitor C1 that are in series (that is the right loop). The authors...

I just need some help understanding some of the theory behind these.. Can anybody help explain the relevance of a time constant in an RC circuit and why the time constant increases as resistance increases? Thanks in advance:blushing:

Hello everyone, I almost got all the parts to this problem: In an RC series circuit, = 11.0 V, R = 1.10 M, and C = 1.80 µF. (a) Calculate the time constant. 1.98 s (b) Find the maximum charge that will appear on the capacitor during charging. 19.8 µC (c) How long does it...

I've been set the following assignment on RC circuits that I thought I understood. Turns out I don't: http://www.geocities.com/danielessex/images/electronicsmain.jpg I understand what is happening in the circuit and what it is asking me to do but I don't really know how to go about it...

I am doing a lab on RC circuits and I do not understand anything about it. In the lab, I charged an discharged a capacitor. The voltage decreased with the equation V=Voe^(-t/RC) Can you explain me this lab? Thanks