rc (for "run commands") is the command line interpreter for Version 10 Unix and Plan 9 from Bell Labs operating systems. It resembles the Bourne shell, but its syntax is somewhat simpler. It was created by Tom Duff, who is better known for an unusual C programming language construct ("Duff's device").A port of the original rc to Unix is part of Plan 9 from User Space. A rewrite of rc for Unix-like operating systems by Byron Rakitzis is also available but includes some incompatible changes.
Rc uses C-like control structures instead of the original Bourne shell's ALGOL-like structures, except that it uses an if not construct instead of else, and has a Bourne-like for loop to iterate over lists. In rc, all variables are lists of strings, which eliminates the need for constructs like "$@". Variables are not re-split when expanded. The language is described in Duff's paper.
Hi, i am trying to design a circuit, where i am trying to light up an LED long enough based on my pulse signal.
Here is what i am trying to do.
a 10us pulse(every second) --->74HCT04 buffer---> (RC circuit)----> LED.
since this is a 10us pulse, i want to make sure to light up the led for...
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...
Homework Statement
An uncharged 1.15 uF capacitor is in series, through a switch, with a 4.50-M Ohms resistor and a 24.0- V battery (with negligible internal resistance.) The switch is closed at t = 0 and a current of Ii immediately appears. (Which I calculated to be 5.33 uA.) How long will...
Homework Statement
A circuit consists of 3 components connected between 2 terminals: A 6 V source, a 60 ohms resistor and a 0.02 F capacitor. The capacitor is initially uncharged. The voltage source is turned on. What is the current flowing through the above capacitor after a very long time...
This is not homework, but a question I have posed for myself.
In a linear, passive, 3-terminal RC network for sinusoidal voltage input how many resistors and capacitors are required to give an open-circuit voltage gain of 2?
I've found some very complicated networks, but I'd like to find...
Homework Statement
They want us to find T, time, when the capacitor has lost 50% of its energy. They give us voltage, capacitance, and resistance.
Homework Equations
I=I_o(e^(-t/RC))
Q=Q_o(e^(-t/RC))
Potential Energy = Q^2/2C
The Attempt at a Solution
I have no idea how...
i can't figure this out. In an RC circuit, why is the maximum voltage of a capactior greater then the maximum voltage of a resistor? can anyone guide me in the right direction
Homework Statement
A circuit consists of a Zener diode, capacitor and resistor in parallel. Voltage to be maintained across the components is 4.7V, power 5mW. Find the values for resistor and capacitor
Homework Equations
(Below)
The Attempt at a Solution
I found the resistance by...
Guass' law and RC
1. Homework Statement
1. Find the potential due to a charged line of charge density lambda. the point of interest is on the axis of the line, and a distance afrom the near end of the lone . the line os of length b. the potential is: k lambda ln(a+b)/a).
2 Show that for...
Homework Statement
Okay, I don't EXACTLY remember the problem statement or the circuit diagram, but I believe I can give enough information to do the problem. On this past quiz, I got 75/100, where there are 4 parts: 2 short answer, 1 part multiple choice, 1 part group test. I got 25 on MC...
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...
[SOLVED] RC Circuit Help
Homework Statement
What is the potential of point a with respect to point b in the circuit shown when switch S is open? Which point, a or b is at a higher potential? b.) What is the potential (after a long time) of point a with respect to ground when switch S is...
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...
Homework Statement
Given an RC circuit which has a Capacitor (C=6\times 10^{-6} F) and a resistor (R=5 \Omega) conected in series to an a.c. voltage source of the form v=V_{0} e^{j\omega t} with a V_{0}=1 Volt. Frequency f=10kHz
a)What is the phase of the current with respect to the applied...
Homework Statement
I can't post pictures as I do normally, so you'll have to deal with the cumbersome attachment method! It's just a simple RC circuit. Resistor on top, capacitor on right side with the sinusoidally varying voltage source on the left...
[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 )...
I am trying to imitate the Airhog zero gravity climber
one of these
http://www.gmhummer.com/forums/showthread.php?t=111
can someone please help me regarding derieving equations for the suction pressure required and regarding selection of motors for driving suction fans.
the toy...
This is an experiment Ill have to write up later, unfortunately I was out for 2 weeks of lectures due to illness. This is the experiment;
Find the values of capacitance C and resistance R in a series combination, given he following apparatus;
1. the unknown RC combination (both in the same...
Homework Statement
The switch has been open for a vary long time, and is then at time T=0 closed. Determine the voltage V0(t) for t>0
Homework Equations
voltage from a discharging capacitor is V*e^(-t/RC) Where V is the voltage stored in the capacitor, R is the resistance and C is the...
Homework Statement
You see this trace on your oscilloscope for an RC circuit. The vertical scale is 5volt/square and the horizontal scale is 50ms/square. What is the time constant of the RC circuit?
Homework Equations
Vc(t) = Vo(e^(-t/RC)
Vr(t) = -Vo * e^(-t/RC)
t halftime = Tln(2) =...
I've seen the designs using the 555 timer as the base and making a 2 led IR emitter. These examples use 5v and only two leds to send the 40k signal. http://www.reconnsworld.com/ir_ultrasonic_555timer40khzir.html
I would like to modify this design to run off 12v and use 8 infrared leds. I...
Homework Statement
In a circuit, the switch S has been open for a long time. It is then suddenly closed. Determine the time constant (a) before the switch is closed (b) after the switch is closed. (c) let the switch be closed at t=0. Determine the current in the switch as a function of...
[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?
Homework Statement
1. What electric field strength is needed to create a 5.0 A current in a 2.0-mm-diameter iron wire?
2. You need to design a 1.0 A fuse that "blows" if the current exceeds 1.0 A. The fuse material in your stockroom melts at a current density of 500 A/cm^2. What diameter...
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...
The problem is in bold and my logic/answers/questions are below. Please check my logic and any help with my uncertainties would be...well, helpful. thx
The switch has been in position 1 for a long time. Determine the voltage drop Vc(0) and V0(0-).
Since it has been a long time the capacitor...
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...
Find v(t) at t=800ms for the circuit in Figure 1.
Ans: 802mV
Writing a single node equation we have
\frac{v(t)-2tu(t)}{5}+0.1\frac{dv}{dt}=0.
Taking the Laplace transform we have
L\left\{ \frac{v(t)-2tu(t)}{5}+0.1\frac{dv}{dt}=0\right\} .
tu(t)\Rightarrow\frac{1}{s^{2}}...
Does the capacitor acts as a current source and the inductor acts as the voltage source in the RC and RL circuits respectively? If so why does the capacitor not act as a voltage source and inductor not act as a current source?
Thankyou
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...
Why the voltage across the capacitor can be measured by connecting a CRO across both the resistor and capacitor ?
actually,i have think of the phase difference and the overall resistance.Still,i can't find the answer.May I get some hints from you?
Homework Statement
A capacitor is charged to 1 coulomb; the capacitance is 9.00×10-5 farads.
Then a switch is closed which puts the capacitor in a closed circuit with a resistor; the resistance is 9.0x10^1 ohms.
Calculate the charge on the capacitor after 4.00 milliseconds. (1 ms = 0.001 s)...
Homework Statement
I'm supposed to find the voltage v0(t) for t > 0 for the following circuit:
http://img516.imageshack.us/img516/5858/circuitta7.jpg
Homework Equations
The first part of the excercise was to find the current io(t). I did this by using the node-voltage method to find the...
I am trying to figure out how to come up with an equation to calculate the voltage
across a capacitor for an RC circuit that is supplied by a chopped / full-wave rectified ac waveform shown below.
The shaded portion is the actual input signal to the RC circuit.
anybody have any ideas ?
Ok, if I have a Battery B, Resistors R1, R2, and Capacitor C in this circuit:
(the ...'s just represent empty space, spaces were getting eaten when I previewed the post)
|----------R1--------|
|......|
B+......|
B-......C
|......|
|---------R2---------|
is this...
Homework Statement
A 1.47 micro F capacitor is charged through a 123 Ohm resistor and then discharged through the same resistor by short-circuiting the battery.
While the capacitor is being charged, find the time for the charge on its plates to reach 1/e of its maximum value.
Homework...
I´m trying to understand a circuit that is build like this:
----###R1###---###C###----
###---------###----------###
-----###L###---###R2###---
How am I supposed to find what frequency (not f=0) the impedance is pure resistive?
What I´ve read has it something to do with the resonant...
Hi everybody!
This is my first post, happy to be a part of this forum!
I have a problem that may be pretty easy to solve, and a few years ago I could've myself, but at the moment I'm stuck.
I enjoy fiddling with electronics during my free time, and I'd like to study the use of a capacitor to...
hey, i need some help with a project i am working on.
what i am trying to do is take a full size car and turn it into a RC car. however, inorder to keep the car street legal, i need to keep all the controls operable by a person. i am using only off the shelf parts and servos that you can...
Hi friends
SHAASTRA 2007 (IIT MADRAS,INDIA) brings you an opportunity to earn a lot of cash and become famous .
Participate in FIRE n ICE event where you have to make a small hovercraft
and compete with others.
For more information look at the link below...
Hello All,
I'm having problem to solved the attached RC circuit.
The initial conditions are: VC1(0)=V, VC2(0)=0, and the qeustion is what will be the VC2 after t1 (t1>>0)?
but i always get VC2(t1)=V which is imposible.
I'm solving it by using i=cdv/dt
3. The Attempt at a...
1. A 6V battery is connected to a 1F capacitor and 3 resistors (R1=1, R2=4, R3=2) R1 is is series with the battery. A junction then appears after R1, which creates 3 different paths, 2 for each remaining resistor, and another for the capacitor. After a long time, what is the magnitude of the...
hi.. i m new here.. quite recently, i hav turned my attention to radio controls. i also built one but blew it up coz of messy power supply.
what i want to know is that if i buy a complete radio control kit from a hobby shop, ll i be able to assmble it myself n ll there be any manuals for...
Homework Statement
http://img515.imageshack.us/img515/7671/untitledtu4.jpg
The Attempt at a Solution
I really don't know how to tackle this question, but here is my attempt anyhow (wrong I know! )
RC=5000*2*10^-6
RC=0.01
V=Vo*e^(-t/RC)
0.99=e^(-t/0.01)
ln(0.99)=-t/0.01...
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...