I tried to conserve the charge on the left plates of both the capacitors as intially the total charge on both is 48 and at t=t0 the total charge is 36(on c1) +4V(V is the potential across c2) so i got V=3 and then i conserved the energy
Initial energy on both capacitor = final energy on both +...
Assume that a resistor R charges a capacitor C, whose other terminal is connected to the ground.
The charge at time t = 0 is assumed to be null and the supply voltage is equal to V.
We have, as is well known, ##i = \frac{V}{R} e^{-\frac{t}{RC}}##. Integrating ##\frac{i^2}{R}## between t = 0 and...
I am a bit confused on a few things regarding photodiodes. Here is are two circuits that I am referring to:
or
For the second circuit the capacitor is not of importance.
Here are my fundamental questions:
1. Why do we need an external voltage?
2. Why do we need a resistor?
3. What is...
Homework Statement
Moderators note: link removed. All images should be uploaded to PhysicsForums.
Homework Equations
V=IR
Series in parallel
Series in current
The Attempt at a Solution
I managed to get the current and voltage of R1 and R2. I've been trying to get the next one R3, but...
Homework Statement
Hi mates, I have problems solving the third part of this exercise, I've already done all the previous calculations.
Given the following circuit, where the switch S is open, the power supply = 50 volts and:
The initial charge in the C capacitor: QC = 0 coulombs
The initial...
The problem: a coil of radius r, length l and N turns, rotating with constant angular velocity ω around an axis perpendicular to its simmetric axis and passing for the center of the coil. The coils is submersed in a static magnetic field, intensity B0, perpendicular to the axis of rotation of...
Homework Statement
Homework Equations
Z = √(XC2 + XL2)
XL = 2πƒL
XC = 1 / 2πƒC
I = V/Z
The Attempt at a Solution
First off, thank you for all of the help this semester. I'm sure you'll be seeing questions from me in the spring also. Here is how I'm thinking about this problem:
1. Using the...
I have obtained an experimental setup of a Marx bank which has electrolytic liquid resistors. In the tubing of the resistors are various strength solutions of copper sulfate. I was told that the electrodes are copper but there appears to be some sort of plating or other reaction occurring...
Thank you for your time and effort. It is much appreciated.
1. Homework Statement
I have attached the problem with the solution to this thread. Basically, the problem asks to construct the circuit model for a generic device by using the data of terminal current and voltage measurements. From...
Homework Statement
Homework Equations
The Attempt at a Solution
I often do circuit. But still there is always stuff i dont get..
I was asked to find
1) I1 I2 I3 immidiately after S closed
2) I1 I2 I3 after sufficient of time
3) I1 I2 I3 immidiately after S opened
Just give me clue please...
Homework Statement
A constant voltage source V with internal resistance r is connected to a load resistor R. The dissipated power by the resistor R is P=RV^2/(R+r)^2. Show that the maximum power dissipated by the resistor R is achieved when R = r. The maximum of P with respect to R is achieved...
Homework Statement
C1 = 4 micro F
C2 = 8 mF
R1 = 4 ohm
R2 = 8 ohm
V = 12
Questions :
1) Find current I when S not closed
2) find Vb, when Vc is 0
3) find Vd, when Vc is 0
4) total charge move from B to D
Homework Equations
Vf - Vi = F.d/q
(not sure this below is useful equations)
I = E/Z
E...
Homework Statement
A resistor of resistance 10Kohms has voltage across it described by the function
V(t) = 6sin(10t+pi/4)*exp(-2t) Volts
Calculate the energy dissipated in the resistor between t=0 and t=0.5
Homework Equations
The Attempt at a Solution
I have done the definite integral and...
Homework Statement
Homework Equations
I = VR
Series = current the same, voltage different
Parallel = current different, voltage the same
The Attempt at a Solution
Is the 1 ohm and 15 ohm parallel? I'm still learning to differentiate it.
If yes, then R = 15/16 ohm
Is the R series to 5ohm? If...
Homework Statement
Homework Equations
at point C:
i2 - i3 - i4
i2 = i3 + i4[/B]
The Attempt at a Solution
I labeled all the currents going through each resistor in the picture[/B]
for loop ABC:
2000i1 = 3000i2 + 4000i3
for loop BDC:
3000i5 = 2000i4 + 4000i3
at point C:
i2 - i3 - i4
i2...
Homework Statement
1. The characteristic decay constant for a capacitor C discharging through a resistor R is the product of R times C. If the initial voltage at time t = 0 is Vo = 13Volts and what is the voltage at time t = 2RC?
2. A capacitor C = 9microFarads is charged from 0Volts to...
Homework Statement
What is the current through the resistor marked 'R' in all three circuits just after the switch is reopened after being closed for a long time?
The Attempt at a Solution
The explanation that we were given for (1) is that I = V/2R and (2) I = V/3R and (3) I = V/(R/2) but I...
Homework Statement
(see my attached photo to better understand where I am coming from!)
So after some research, I've discovered that the current at different points in a simple series circuit is supposed to be the same value, and that the voltage is supposed to be different values.
I...
Hi guys!
(see my attached photo to better understand where I am coming from!)
So after some research, I've discovered that the current at different points in a simple series circuit is supposed to be the same value, and that the voltage is supposed to be different values.
I performed a lab on...
Homework Statement
Res-monster maze. In Fig. 27-21, all the resistors have a resistance of 4.0 and all the (ideal) batteries have an emf of 4.0 V. What is the current through resistor R? (If you can find the proper loop through this maze, you can answer the question with a few seconds of mental...
I= Current flowing
V1= Voltmeter 1
V2= Voltmeter 2
My question is that if there would be any difference between the readings of V1 and V2?
We know that: By Ohm's law: V= I.R
also:
Combined resistance of R1 and R2 will be:
1/RCombined Resistance of R1 and R2= 1/R1+1/R2
The reading in V2...
Saw an old thread, "Led Lights Burn With Power Off" and it was closed... so let me check out an issue with you all: in this same situation and I don't want the lights softly glowing, could I put a 100 ohm 1/4 watt resister in line to block the teeny tiny induced current?
Would it behave well...
Can a wire be called a resistor? Also do all circuits require a resistor? If no then give an example of a circuit which doesn't have a resistor. Please thanks
Homework Statement
In order to provide full scale deflection the coil current required in a galvanometer is 190μA and the resistance of the coil in the galvanometer is 35Ω
- What is the value of the resistor to be connected in parallel with the meter so that full scale deflection is obtained...
Homework Statement
Starting from the expression of the Delta-Y resistor transformation work out the conductance transformation equation.
Homework Equations
3. The Attempt at a Solution [/B]
I will just be using one equation as others are done analogically. My Δ has ##(R_{12},R_{23},R_{13})##...
I am working on a project for a cube-sat to go up on a balloon to 40 km. My team has been talking to some other groups who have worked on other cube-sats who say that our resistive heaters need to be Kapton heaters rather than 1D heaters like what we have designed for. They claim that our...
Homework Statement
The problem from the textbook is:
Is it possible to connect resistors together in a way that cannot be reduced to some combination of series and parallel combinations?
Homework Equations
V = IR
kirchhoff's current law
kirchhoff's loop law
The Attempt at a Solution
I am...
Hi everyone, I am having problems figuring out how to solve a particular problem.
Because I was not able to access PhysicsForums recently, I typed everything about my issues into a pdf file that I have attached below.
I am grateful for your help in advance, and make it a great day...
Homework Statement
When the switch is open, the voltage is ##U_{ab}##. When the switch is closed the calculated max current is ##I_{max}##. Calculate the resistance of ##R_p## when its power is max and the current of ##I_g##
##R1=100,R3=200,R4=400##,##0<Rp<100## and...