Resistor Definition and 879 Threads

Homework Statement For the RC Circuit (R = 100 Ohm, C = 100 Micro Farads, and an open switch at t=0), we know that the capacitor is charged to a voltage of 10 V prior to T=0. Find expressions for Vc(t) and Vr(t). Homework Equations Vc(t) = Vi * e(-t/rc)The Attempt at a Solution Vc(t) =...

Homework Statement The voltmeter shown in the figure below can be modeled as an ideal voltmeter (a voltmeter that has an infinite internal resistance) in parallel with a 11.0-MΩ resistor. Calculate the reading on the voltmeter for the following. R = 1.1 MΩ R = 10.8 MΩ R...

So i have a general question that I came across with source transformations, but this question can be classed as a beginner question. When I find the equivalent resistance, how do you determine whether or not it is in series or parallel with a source?

The meter in the circuit shown in the image has an uncalibrated linear scale. With the circuit as shown, the scale reading is 20. Find the scale reading when another 2000Ω resistor is connected across XY.

Find the current in I3 resistor by using kirchhoff's laws. problems: -when i try to use norton theorem to check for my answer and my answer is IN=2.855A=I3 but when i use kirchhoff's law i get I3=0.645A. -i don't know where is the problems...the current for norton theorem and kirchhoff's...

Homework Statement If I have a coaxial transmission line, with a resistor halfway through, and another resistor at the end, how do I calculate the reflection coefficient for the spot where the resistor is halfway? Here is a diagram of what I mean. Dashes and dots are are the lines, and }...

Preface: Newbie here. Sorry if this has been asked before - I did have search but couldn't quite find what I was after. Also, I'm not putting this into the electrical engineering section because I don't want what will inevitably be an electrical engineer's answer =) Here goes: Voltage across...

I have a 400A (125VDC) charger that feeds a battery bank and a few DC panels (critical). This poor design has the panels being fed from the high side of a 600A breaker that is between the charger and battery bank. I need to take the battery off line for a load test but the problem I'm going to...

I am having a lot pf problem to attempt this question, please help me, i am stuck..! The power loss P in a resistor is calculated using the formula p=v^2/R The uncertainty in the potential difference V is 3% and the uncertainty in the resistance R is 2%. What is the Uncertainty in P...

Homework Statement A resistor of resistance R is connected to an AC generator with EMF(t)=(EMF_max)sin((w_d)t). (a) Write Kirchhoff's Loop Rule for this circuit at a particular instant of time. Is your result a differential equation? (b) Find the current as a function of time. Now...

Homework Statement The question itself doesn't make sense to me, it says to find emf but the answer box has V= ? problem is an attachment. Homework Equations I=e/(r+R) Ir+IR=emf P=VI The Attempt at a Solution If it wants voltage that's simple P=I^2R P=V^2/R V=54.8V if...

Hi guys, new here. I was wondering if anyone knew of a way to trick a 12 volt transformer into seeing more load. I have these lights http://www.lowes.com/pd_172832-24969-800CBL5N_0_?productId=1207073&Ntt=tiella&Ntk=i_products&pl=1&currentURL=/pl__0__s?newSearch=true$Ntt=tiella$y=0$x=0" and it...

If a current of .587e^j1.12 is passing along a 200ohms resistor, how would I go about calculating the power dissipated in the resistor?

Homework Statement Determine the value of the ballast resistor is satisfactory if a 5Volt 0.5 watt zener diode is used in the circuit sorry can't upload a picture but basically VS = 15v min to 20v max R ballast = 90 ohms (series with zener) and R load (in parralel with Zener) is 50...

Homework Statement http://farm5.static.flickr.com/4117/4775531139_8d4dd954f5_b.jpg Homework Equations I = V/R E = I1R2 = I2R2 =I3R3 The Attempt at a Solution I got 5.22 ohms for part (a), but I'm not sure how to go about calculating the amps through a specific resistor.

Homework Statement Consider the electric circuit shown in the figure. Assume that V = 10.4 V, R1 = R2 = R3 = R4 = R5 = 3.00 Ohm. What is the electric current flowing through resistor R2? I couldn't upload the figure, but you can find it on my cramster.com post...

Electrical Engineering-- Capacitor Resistor Circuit Homework Statement Hello all. First time posting so excuse any fourm faux pas I may make. I was wondering if anyone could lend some help with the circuit below (ignore the *, they are just space holders to prevent reformatting of the...

Homework Statement Number 15 http://lookpic.com/d2/i2/386/kFYE2mOH.jpeg [PLAIN]http://lookpic.com/d2/i2/386/kFYE2mOH.jpeg Homework Equations Rs=R1+R2+R3 Rpar=1/r1+1/r2+1/r3 I=V/R The Attempt at a Solution 1/(1/5+1/10+1/5)=2 Rtotal=7 I=21/7 I=3 I don't know what else to...

i have a question about resistors. i thought they were described by their resistance - 20 ohm, 40 ohm, 2 Megaohm, etc. how come I see "power" values on resistors? for example my lightbulb says 40 watts. but i thought the power is simply P = V^2/R and that would depend the voltage of my power...

Homework Statement Why is it that the output is equal to V+ (when the switch is open) in diagram A, if there is no current flowing? Why is it that A (1/0) is used by convention? I mean the lamp I got at home has a "0" for off and "1" for on, on the switch. This is confusing me...

Homework Statement See figure Homework Equations Rs = R1 + R2 Rp = (R1*R2)/(R1+R2) The Attempt at a Solution I tried completing one repitition of the pattern to see if I could figure out what the Req would be so: R + R in series on the end so 2R // R so 2/3R in series with R...

Homework Statement For the circuit below (attached) plot the amplitude of AC voltage across resistor as a function of the angular frequency of the ac source. Homework Equations ZR = R The Attempt at a Solution I'm not really sure about any of this. Across the resistor, the complex...

What is the resistance of a non-ohmic resistor (lamp) in v-i graph given a voltage? I thought it would be the gradiant for specific voltages. But apparentlly it is the ratio of the specific voltage/current which makes sense too. So what is the correct out of the two?

Homework Statement How would you calculate the voltage at a specific resistor given that it's a parallel circuit.

Homework Statement A problem from a translated Sears-Zemansky, 1965, 14-10: A conduction coil with inductance of 15 miliHenrys and resistance of 10 Ohms, is connected in line with a capacitor of 200 microFarads and a resistor of 12 Ohms. The circuit is supplied with an alternating current of...

Homework Statement What is the resistance of the (semi-)infinite resistor chain below, between points A and B, if R = 25 ohms? The Attempt at a Solution I am not sure where to begin exactly, but I am thinking of this formula: VAB=VB-VA=∑ε-∑i.R or...

I have a circuit that uses a resistor to drop the input voltage. From my calculation, the power dissipation thru the resistor is less than it's wattage rating but yet the resistor is hot to the touch. Should I use a bigger resistor because it's too hot to the touch or should I keep using it...

Homework Statement heres a picture of the problem. Please don't give me the answer just tell me what are the steps to complete it. thanks. http://i307.photobucket.com/albums/nn296/alan1592/download-1.jpg Homework Equations V=IR The Attempt at a Solution 1/6+1/3=2 Ohms

Hi! A little food for thought for people who like high school physics labs.. In a standard rheostat(I have seen only the cylindrical one..the question is about rheostats of this shape..), we find a metal wire wound over a cylindrical core. The wire is wound with very closely spaced turns...

1. In the case of a current source in series with a resisitor, can this be transformed to just a current source with 0 resistance, or is the resistance infinity in the Norton equivalent? Homework Equations The Attempt at a Solution My teacher told us this in class but i can't...

Homework Statement Determine the potential \phi inside a resistor of length l and radius a. Also determine the current density J, resistance R, surface and volume charge density Pe and Pes. The resistor is homogeneous. Homework Equations The Attempt at a Solution V=Ed, d=l here...

Homework Statement Given that the souce voltage = Vo, find the Current at resistor 4. Homework Equations For resistors in series, I = constant For resistors in parallel V = constant The Attempt at a Solution So I gather that since the block containing resistors 2-5 is in...

Homework Statement [PLAIN]http://img297.imageshack.us/img297/7053/96217079.jpg given this circuit find the current on R1,R2 and R2Homework Equations I = V/RThe Attempt at a Solution i applied kirchhof's law and I have this: 36 - 5*I - I1*4 = 0 36 - 5*I + 20 - 2*I2 - 14 = 0 20 - 2*I2 - 14 +...

Here is the problem and the equations I feel are relevant. The instructor was not clear on whether or not R2 was moving with velocity v, but I assume so because something must be moving (I think). Can somebody give me some instruction on where to go from what I have...

Homework Statement please see attached picture. Homework Equations The Attempt at a Solution

Homework Statement There is a Battery connected to a single loop circuit containing two resistors, R1 and R2, and one capacitor L. After a long time, the battery is removed, so there is a single loop circuit with just two resistors and a capacitor. What is the current going through R1...

I have a unit that measures temp with a thermistor. I want to use it to measure voltage. I am trying to build a circuit to emulate a thermistor. Here are the parameters. 24v control = 37.8K. 1v control change = -1k so there is an inverse relation ship. Control voltage range = ideal is 6...

URGENT: Finding the Current and Power across each Resistor in a Complicated Network Homework Statement For the circuit below, a 12 V batter is connected across the points a and b. Determine the following: a) the equivalent resistance between points a and b b) the total current flowing...

Homework Statement Find the voltage across R1 (see attached image). Note that all values are known. Homework Equations Voltager divider might be used. I hope KVL doesn't have to be used here. The Attempt at a Solution My problem is that I don't know if the current from I1 is...

Homework Statement Thermal energy is to be generated in a 0.31 resistor at the rate of 11 W by connecting the resistor to a battery whose emf is 2.1 V. (a) What potential difference must exist across the resistor? (b) What must be the internal resistance of the battery...

Homework Statement In the pictured, the battery puts out 12 volts, R1 is 9 ohms, R2 is 6 ohms, and R3 is 5 ohms. What current flows through resistor R1? Please use only SI (metric) system units in your answer! Homework Equations R=V/I ? The Attempt at a Solution I am...

I am confused on a question that arises in my mind: that is "After passing the resistor the amount of current flowing through cross section of area is decrease or the energy of charges i.e Potential decreases".

I need some help identifying what I'm pretty sure is a resistor. I have a power supply that blew up, I opened it up and everything looks ok except for this. The color bands are: Brown Blue Silver Gold Black The only problem is that silver isn't a valid color for the third...

Homework Statement I'm confused because in my textbook, it says that when R is large, there is very little current and if it is small, there is more current through it when there's a potential difference across the resistor...but like in another book, it says that current is not used up when...

1. What is the current through each resistor 2. All the obvious stuff... 3. Ok, without showing all my work, here's what I have solved and know is right: The equivalent resistance of the whole circuit is 56.3 ohm. From this, I used Ohm's law to get the equivalent current for...

Homework Statement A variable resistor, R, is connected to the terminals of a battery (dashed box in the diagram). The graph below shows data collected in the circuit as R is varied. What is V0, in volts? What is the internal resistance, r, in ohms? should the V0 be measured at the top...

Homework Statement Five resistors with resistance R1 = 4.90 Ω, R2 = 7.30 Ω, R3 = 8.80 Ω, R4 = 2.70 Ω, R5 = 5.00 Ω, are connected to a battery with emf E = 8 V in the circuit shown. What is the current in resistor R1? I also need the current through all other resistors. I know you need to use...

Homework Statement The heating resistor is rated at 10ohms and 1W. By how much was its power exceeded? Why didn't the resistor burn up? This is a question taken from an Electrical Equivalent of Heat lab assignment... here is a link to the exact same lab we did...

Circuit: Here's the circuit: there is a 8V battery. The charge leaving it reaches a junction: if the current "turns right" it goes to a 12 ohm resistor (R1) and can then loop around back to the battery, if it goes straight (i.e. takes other path at junction) it runs into a 4 ohm resistor (R2)...

http://www.webassign.net/tipler/26-50.gif I presume the 4 ohm resistor is parallel with the diagonal 2 ohm. It's equivalence is parallel to the vertical 2 ohm. Then, the result is in series with the 3 ohm. I then substituted values in V=IR and worked backwards to find the current and...