Rc Definition and 643 Threads

Homework Statement Suppose a 120 micro-farad capacitor from a camera flash unit retains voltage of 210 V when an unwary student removes it from the camera. If the student accidentally touches the two terminals with his hands, and if the resistance of his body between his hands is 1.8...

Hi all, I think this issue periodically resurfaces in PF. I have found a similar discussion in this closed post and possibly others. I'm posting this because I'd like to check my understanding, if anyone is available to provide some furtherinsight. So I'm trying to gather a "overall"...

I want to know about RC band pass filter ! more specifically details about the graph of voltage vs frequency.. how the curves goes up and why the curve goes down? I don't understand ... please help me out

Homework Statement Homework Equations Vc = ( Initial Voltage - Final Voltage ) e(-RC/t) + Final Voltage 3. The Attempt at a Solution I got the answer through Laplace but am not getting through time domain analysis. Given q across C is 2.5mC C = 50micro F q = CV So V = 50V Initial voltage =...

I have a RC circuit which also includes a battery, the capacitor has some charge initially before we put all the components in the circuit. Now as I connect all of them then charge will start to flow, but wheather this charge will be the sum of initial charge on the capacitor and the new charge...

Hello , I am thinking to work on a RC aircraft ( Airplane ) that can load a small supply of Medical Firstaid in small range. So I need to make it fast and stable. So I'm thinking to use a small Turbo-jet engine in it which will be home-made. Please suggest me -- (1) Is that makes any sense ...

Homework Statement Find ##i(0^+) ## and ##i(t), t≥0^+## Homework EquationsThe Attempt at a Solution [/B] I'm having trouble finding the current through this capacitor. I tried using a KVL loop for ##t=0^+##, but I'm doing it incorrectly or something. Earlier in the problem I found...

Homework Statement Homework EquationsThe Attempt at a Solution I'm kind of lost now, how do I go about getting this into the right form for partial fraction exapnsion. And also what do I do with the V(0'). There was no information given about it.

So this is an example given to me in one of the guides. I am somewhat confused as to why R and R1 are considered parallel when the switch is closed at t=0. I thought that the two resistors cannot be parallel since there is a voltage source between them. One hypothesis I had was to treat it...

A 50Hz AC source of 20V is connected across R and C. The voltage across R is 12V. The voltage across C is?

1. 2. V=IR, Q=CV3. To calculate the current in the circuit in the case when the switch is open and steady state is reached, I assumed that no current will flow "across" the capacitors and so the current I will simply be emf/(r+R1+R2) = 12 V/(1+3+2) = 2 A. The voltage drop across r would be...

Homework Statement I have to find the charge ##q## on the capacitors (all have capacity ##C= 4 \mu F##) and ##\mathscr{E} = 12 V##, ##R=50 \Omega##Homework EquationsThe Attempt at a Solution I wrote the nodes current equations ##\begin{cases} i_{1}+i_{2}=i_{3}\\ i_{3}=i_{4}+i_{5}+i_{6}\\ ...

Homework Statement At initially, the switch is open meaning there is no current flowing. So how does the capacitor is initially charge to -5V? and what does a negative voltage capacitor means? I thought it is only when the switch is closed (t=0) that when the capacitor is being charged...

Homework Statement Homework Equations ##q = CE(1 - e^{-t/RC})##The Attempt at a Solution I assumed that, since the problem specifies that sufficient time has passed, it meant to say that enough time passed. thus making the exponential term in the equation go down to 0, and the charge in the...

Homework Statement Three lamps are rated 110 V, 60 W. They are connected in parallel and a capacitor is connected in series with the group. The circuit is then connected to a 230 V 50 Hz power supply. Detremine: a) The capacitance which is required to provide the correct voltage across the...

Homework Statement Homework Equations ##V = ZI## ##Z_R = R## ##Z_C = -\frac{j}{\omega C}## ##Z = \sqrt{R^2 + (\frac{1}{\omega C})^2}## ##P_{av} = \frac{1}{2}V_m I_m cos(\phi)## ##\phi = arctan(\frac{-1/\omega C}{R})## ##\Delta \phi = \phi _1 -\phi _2## The Attempt at a Solution I've found...

In the derivation of discharging RC circuit, you use I = -dq/dt to get Q = Q0 e-t/RC But isn't dq/dt already implied to be negative, since charge on the capacitor is decreasing, and you force it to be negative using initial nd final conditions? So the final state is some low charge q, and the...

I have a circuit which it looks like this. We need to write the general RC equation.Can I reduce this circuit to like ##R_{eq}## and ##C_{eq}## then solve it ? This is not a homework question.Just need theoretical approach

Homework Statement Homework Equations For a basic RC circuit during charging: q = CV(1-e-t/RC) i = V/R (e-t/RC) The Attempt at a Solution I can solve basic RC circuits but this is just out of my realm of understanding. I can also find the max charge of the capacitor. I'm not looking for...

Hi guys, I'm working on a project where I need to find the torque produced by the rear wheels of an RC car so that I can convert it into power and then into the current required by the motor. So T=ω×Pmech → Pmech → Pelec → Imotor Here are the details for the car: 1kg weight Torque on each rear...

Homework Statement See attached image for circuit diagram and givens. The switch has been closed for a very long time. a) What is the charge on the capacitor? b) The switch is opened at t=0 s. What current initially flows? Homework Equations V = IR Q=CV I=I0e-t/(RC) The Attempt at a Solution...

I was talking to my Physics teacher about this at lunch. If I was to have an rc Helicopter which i had hovering perfecting (if only i had the skill) on a train at rest. What would happen in terms of the position of the helicopter as the train accelerated? Would is stay at the same point in...

Homework Statement How to determine the current as a function of time that flows in 10 ohm resistor, 100 ohm resistor, and 15 microFarad capacitor? Please help Homework Equations I = V/R I_capacitor = I e^(-t/RC) The Attempt at a Solution I only know the equation V=IR and the capacitor...

Homework Statement R1 = 10 kohms R2 = 15 kohms C = 0.4F Voltage source = 20 V At first, the switch is closed for a long time so that the capacitor reach its steady-state condition. Then, the switch is opened at t=0. How much does the current flow across R_2 at t= 4ms? Homework Equations I...

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...

Homework Statement An electric circuit is shown as above. The switch S is closed for a long time and the current flowing is constant. Given that C1 = 3 μF, C2 = 6 μF, R1 = 4 kΩ, R2 = 7 kΩ If the power at R2 resistor is 2,4 W a) Determine the charge at C1 b) When the switch is opened, after...

Homework Statement A circuit is constructed with four resistors, one capacitor, one battery and a switch as shown. The values for the resistors are: R1 = R2 = 41 Ω, R3 = 68 Ω and R4 = 154 Ω. The capacitance is C = 49 μF and the battery voltage is V = 12 V. The positive terminal of the battery...

Homework Statement Hello everyone , this question has been troubling me for weeks,so if anyone could please help me out.i have attached the pic of the question.The answer given is 2 seconds but i am getting a different answer. Homework Equations first of all i distributed the charge on the two...

Homework Statement I have a red mystery box which contains a 20, 50, 100, and 200,000 ohm resistor (one of each and ONLY one.) There are three terminals on the box you can plug a voltmeter into... testing A-B I got 60k, testing A-C I got 140k, and testing B-C I get 120k ohms. So this is a bit...

Homework Statement In a simple RC circuit the current as a function of time behaves in the following manner: I(5s) = 8.823 I(10s) = 7.788 I(20) = 6.065 I(30) = 4.724 I(40) = 3.679 I(50) = 2.865 I(60) = 2.231 I(70) = 1.738 I(80) = 1.353 I(90) = 1.054 I(100) = 0.821 I(110) = 0.639 Assuming...

Hi I am trying to run an RC oscillator using a 2N3904 (Datasheet for reference: http://www.kynix.com/uploadfiles/pdf8798/2N3904.pdf) The circuit looks like the following. I want to run it at 0-5v but I failed, I assume it is because the voltage is not high enough? What would you expect the...

Homework Statement In the figure given what is the Thevenin resistance between the nodes of the capacitor?? Homework Equations The Thevenin resistance is the open node resistance between two points. The Attempt at a Solution The way I see it, R2, Rf and R1 are in series and that combination...

Hi, I am working on RC OScillator Circuit, but i had problems with adjusting frequency. I can adjust frequency but it effects amplitude too (amplitude is changing while adjusting frequency), how can i separate these two variables ? I mean, when I am adjusting frequency, I want to amplitude...

Homework Statement The circuit in the figure below has been connected for a long time. Let R1 = 8.20 Ω and R2 = 4.40 Ω. (a) What is the potential difference across the capacitor? (b) If the battery is disconnected from the circuit, over what time interval does the capacitor discharge to...

Homework Statement In the circuit of the figure below, the switch S has been open for a long time. It is then suddenly closed. Take = 10.0 V, R1 = 56.0 kΩ, R2 = 200 kΩ, and C = 14.5 μF. (a) Determine the time constant before the switch is closed. (b) Determine the time constant after the...

Homework Statement 1. (35 pts) You have a coop job helping to test a capacitor energy storage system. There is a rather large capacitor with capacitance, C = 2.02F. It is charged to a potential V = 602.V with the polarity of the capacitor as shown. The large, solid line on the right of the R–C...

Homework Statement In the figure below, suppose the switch has been closed for a time interval sufficiently long for the capacitor to become fully charged. (Assume R1 = 11.0 kΩ, R2 = 22.0 kΩ, R3 = 4.00 kΩ, and C = 11.0 μF.) (a) Find the steady-state current in each resistor. (b) Find the...

Homework Statement Switch S shown in the figure below has been closed for a long time, and the electric circuit carries a constant current. Take C1 = 3.00 μF C2 = 6.00 μF, R1 = 4.00 kΩ, and R2 = 7.00 kΩ. The power delivered to R2 is 2.30 W. (a) Find the charge on C1. (b) Now the switch...

Homework Statement A voltage source E_0 cos ωt is connected in series with a resistor R and a capacitor C. Write down the differential equation expressing Kirchhoff’s law. Then guess an exponential form for the current, and take the real part of your solution to find the actual current...

Homework Statement Homework Equations Voltage Division v2 = vs * (r2/(r2+r1)) KCL - sum of all currents at a given node is 0 V= i * r The Attempt at a Solution [/B] This is my solution...

Homework Statement Find Vc(0) Homework Equations Nodal Eq , ohms law The Attempt at a Solution Can someone please check my work for Vc(0)? I'll appreciate it.

Homework Statement 2. Homework Equations [/B] KCL, Node Analysis , Mesh Currents The Attempt at a Solution Hi, in part b when t>0 the capacitor is replaced by an open circuit , however in part c the capacitor is replaced by a short circuit why is that?Aren't inductors the only ones...

hi, i have a question which i was hoping someone could help with,a series circuit featuring a capacitor (C) charging via a 1Mohm (R) resistor and a 12volt dc supply(VS).i know the equation to describe VC is VC=VS(1-e -t/RC)the question is: assuming VC is 2V after a time of 4 seconds, determine...

I have problems with question b. I don't know where to start. If the switch is on steady state, the current through capacitor would be 0 and i can't have K. This makes me confused. This is the Total response function of a): V0(t) = K^(-1/2t)

In the figure below in e1 1.64 why is i(t) negative. When switch is put to S1 position, the capacitor will start discharging. So current will flow from top plate of capacitor to resistor to bottom plate of capacitor. Where did negative sign come from in eqn. 1.64? When charging the current...

I am assigned to design a circuit that peaks voltage at 10kHz and is less than half peak voltage at 3k and 30k. Only capacitors and resistors are allowed. The circuit I'm using is attached. I end up with ##I_0 = [\frac{-R_2\omega^2C_1C_2 + [C_1+C_2]R_1R_2\omega^3C_1C_2 - R_1\omega^2[C_1+C_2]^2...

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...

Homework Statement A three phase 220 V , 60 Hz, six poles 10 hp induction motor has the following circuit. Parameters on a per basis referred to the stator: Rs = 0.334 Ω, R’R = 0.147 Ω, Xs = 0.498 Ω X’R = 0.224 Ω , Xm = 12.6 Ω The rotational losses including the core losses amount to 262 W...

Homework Statement Homework EquationsThe Attempt at a Solution so when t=0, the capacitor is a closed circuit. The Req of the circuit is (20k)(30k)/(20k+30k)= 12000 ohms. U = I Req = (7.5x10-3A) (12000 ohms) = 90 Volts so there is a voltage drop of 90 volts across the 20k resistor (R1)...

Is it possible to make a 2nd order CR LPF or HPF where the cut off frequencies for each pole are equal? Here is a calculator for this system which includes the transfer function.http://sim.okawa-denshi.jp/en/CRCRkeisan.htm I figured that I need to try to solve the denominator of the transfer...