Resistor Definition and 879 Threads

1. The 10 ohm resistor in the figure is dissipating 40W of power. How much power is the 5ohm resistor dissipating? 2. P = I2*R 3. I = sqrt(P/R) = 2. I then did P = I2R = (4)(5) = 20 which is incorrect.

Hi experts, i am wondering if i want to have a few ohms of resistance but does not have any resistor and i use coil a wire that produce a resistance of a few ohms, how different is this 'resistance' compared to the resistance from a resistor of the same ohm value ? I know that a coil produces...

if my 12v motor draws 10amp when running am i right to think if i put 6v on the same motor it will run at half speed? how would i work out the resistor needed to do it? i think i need to be using ohm's law somehow but can't remember just how,its been a while since I've needed to do something...

Homework Statement I understand the maths... I'm here to ask WHY we have to do it this way. The question states: "The power dissipated in a resistor is given by P= E^2/R. If E=200 and R=8 , find the change in P resulting in a drop of 5 Volts in E and an increase of 0.2 Ohms in...

I searched practically all of the nets and webs and still my questions are unanswered, so I decided to consult y'all. I have previously asked you guys about diode sizing to prevent back emf on a relay and you were very helpful. I am once again calling upon your help. I have some relays in my...

Hey, so I have this loop circuit that has some input voltage V in series with a resistor with a resistance of R and another in series resistor that is my load resistance, let's call it G. V and R are not variables, only G is. I know that because of Jacobi's law, to maximize the power...

Consider this circuit with R1 = 30 ohm, R2 = 10 ohm, R3 = 10 ohm, R4 = 20 ohm, R5 = 60 ohm. (the circuit is attached) A. What is the current across the resistor R2, if a voltage of 110 Volt is applied to the two terminals at the bottom of the figure? B. What is the voltage drop across R2...

I am having problems understanding how a resistor resists or limits current flow (or electron flow). http://img714.imageshack.us/img714/5595/currentquestionimage.jpg In circuit 1, if I understand correctly the current at Point 1, Point 2 and Point 3 are all the same – that is if you...

1. If I know the voltages on both immediate sides of a resistor...lets say v1 is on voltage on left side of resistor, and v2 is voltage on the right side of the resistor, is the votage of the resistor = v2 - v1 if the positive side of resistor is to the right? Or can you not even calclulate the...

If I know the voltages on both immediate sides of a resistor...lets say v1 is on voltage on left side of resistor, and v2 is voltage on the right side of the resistor, is the votage of the resistor = v2 - v1 if the positive side of resistor is to the right? Or can you not even calclulate the...

Homework Statement Find current flowing through each resister, voltage across each resister and power consumed by each element in the following circuit. See the attachment Homework Equations The Attempt at a Solution The question I want to ask here is that is the current...

Hi, will I damage the IC (it is 74LS07) if I select a pullup giving 20 mA of current trough the open collector (without any other load)? I looked at the datasheet but I can't figure which parameter should I be looking at (because they give HIGH-level output current of 250 micro amps. What I...

In an alarm clock, there needs to be a delay of 1 minute between closing switch and circuit being active. A 2200microF capacitor is charged through a resistor from a 5V supply. The pd across capictor must rise to 4.3V for alarm to become active. Calculate size of resistor. The answer is...

Hi, I am going through some texts but it was not very clear.I hope some experts here can help me on this. The max voltage across the relay and stabilising resistor is given by; (If/N)(Rs+Rb) where If - max short circuit rating, A N - current transformer, CT ratio Rs - CT internal...

Hi guys, I was reading about monte carlo analysis in the introduction from a textbook, and they gave an example of a voltage divider. They assumed resistor values had an equal probability of having values between the two tolerances. I know this is a simplistic assumption and I was wondering...

I am looking for a resistor that can dissipate a constant amount of heat at all temperatures immediately. I have been using some metal film/oxide resistors, but it takes a very long time before the resistor starts radiating heat. I think the material making up the resistor has such a high...

Hey again. I have a circuit that I've made and I was told I should put resistors in so that I don't blow out my transistors and buttons. Ok, I can do that... but I have no idea what size of resistor I need! Picture: I'm using TIP41C Transistors: http://www.drixsemi.com/TIP41C.PDF...

I have a tiny bit of current fluctuation on one of my lines. If i put a lil 500ohm resistor in the line the osillations on the other end substantially decrease. Why? Does the resistor effectively 'absorb' these oscillations?

I posted this question in the physics forum with no luck, the concept has to do with physics but it's applications is within the body. It is found in the lung and also in venous return curves, when central venous pressure drops below 0. Basically, I am asking how the concept of zone 2 in the...

In my home I am getting 220 AC Volts of electricity. I want to connect white color Light Emitting Diod (LED) that requires 3 volts output with the resistor which will be connected to 220 Volts power. So can anybody please tell me what is the formula to find that how much voltage is output from a...

Homework Statement In the circuit the emf is 150V connected across a resistance network. Each resistor has a value of 10 ohms. What is the current through R2? Homework Equations R=V/I The Attempt at a Solution I found that the resistance of R2 and R3 because they're in a series is...

Is a Light Dependent Resistor (LDR) resistant to water? Will there be any problems if it is exposed to water directly?

Homework Statement What direct current will produce the same amount of thermal energy, in a particular resistor, as an alternating current that has a maximum value of 2.60 A? Homework Equations The Attempt at a Solution A DC would dissipate a constant amount of thermal energy in a...

Homework Statement (a) For the circuit below, the value of R is adjusted so that each of the two 10Ω resistors dissipates 10W. Calculate the value of the variable resistor R. (b) What is the value of R if it is adjusted to dissipate the maximum power possible? For this value of R...

Hello Everyone, I was spending some time today organizing my resistor collection into drawers when this nagging question came to mind. How did they come up with the standard resistor values that we have now? There must have been some kind of rationale to it as one would normally expect the...

A resistor draws a current i=8sinwt at a voltage of v=200sinwt. Calculate the average power dissipated in the resistor. What i did is p=ui = 1600sin^2 (wt) and i got stuck:P i don't think it's the right equation.. the answer should be 800W .. and that's nothing like it. Could someone help me ?

Homework Statement Consider the resistor network shown in the figure below, where R1= 5\Omega and R2= 7\Omega . (a) Find the equivalent resistance between points a and b Req=([1/6 +1/5]+7)+12+6=(9.73)-1+18-1=6.32\Omega (b) If the potential drop between a and b is 12 V, find the...

Homework Statement In the circuit of figure p28.23, determine the current in each resistor and the potential difference across the 200 ohms resistor. http://s848.photobucket.com/albums/ab41/tag16/?action=view&current=circuit.jpg&newest=1 Homework Equations 1/Req= 1/R1+1/R2+1/R3+1/R4...

I want to find the increase in the temperature of a resistor due to joule heating. I mean that if we apply some electrical power to a resistor then the electrical energy is converted to heat energy due to joule heating. The heat energy will increase the temperature of the resistor. Is it...

Hello Forum , I would like to ask you about the resistor value ideal for a laser module 3V @45mA and the power supply is 3.3V , R= (3.3-3)/45= 6.6 ohm ? it sounds a little strange to me. Have a nice day and thank you in advance.

If a resistor is connected parallel to a straight wire joining the two terminals of a battery, does any current pass through the resistor. Is there any current in the circuit?

Homework Statement hi guys, i'm having trouble applying Kirchhoff's laws to determine the equivalent resistance of this symmetrical array of resistors (see attachment); i think there is a quick trick, using 4 current loops, but i can't remember it... nor find relevant documentation – this is...

Circut help! Homework Statement In the circuit shown below, the batteries have negligible internal resistance. (a) Find the magnitude of the current in each resistor. I3 = ?? A I4 = ?? A I6 = ?? A Homework Equations V=IR i don't know where...

Homework Statement In the circuit shown, the same current must flow through all three componets as a result of conservation laws. Using the fact that the total power supplied equal the total power absorbed, show that the voltage across resistor R2 is given by: v_{R_{2}} =...

http://img5.imageshack.us/img5/6889/imagepf.jpg I need to create a formula using R (resistance), U1 and U2 (voltage) for the current flowing through the 8 Ohm resistor. I've been looking at this for hours now and I still don't even know where to begin. Can anyone get me started on this?

Homework Statement http://dl.getdropbox.com/u/119186/Picture%201.png Homework Equations I = I2+I3 I= e/R The Attempt at a Solution http://dl.getdropbox.com/u/119186/snapshot-1253898419.920882.jpg As you can see I got all of it, but part C. I can't figure out what the process...

I'm designing a circuit for experimental use. I'll make this as quick as possible. Browsing other circuit designs on the web, I initially noticed "followers" placed between other op-amp app's (adders, integrators, inverters, etc). From what I can tell, putting in followers like this must be...

I am trying to determine ohms and wattage of R2 on attached schematic. The resistor fried so I can't tell anything about it This circuit is a recharger for a cordless black and decker drill Thanks

Homework Statement Find Voltage/Current across each diode: ----R--- |...| V...D |... | ----R--- Repeat 50x until...

Homework Statement Hello: I've this circuit: -----Resistor (100000 ohms)---/ (switch) ------- | | |A Battery Capacitor Inductor | |...

Can someone explain how I can find the resistance of an ohmic resistor of unknown resistance by setting up a simple circuit using a voltmeter and household appliances? Thanks

In a filter where 1/4 watt resistors is enough would the filter be less noisy if I use 1/2 watt or more or should I use the least wattage resistors needed?

Homework Statement How much power is dissipated by R1 resistor? (R1=15 W, R2=25 W, V=9 V.) Homework Equations I=V/R P=I^2R The Attempt at a Solution Since it is a series 1/Req=(1/R1)+(1/R2) Then I=V/R= .96 A so Then i just simply plugged in I in P=I^2R which is...

Homework Statement Basically, this "battery" is actually a variable voltage source. The current is raised and the voltmeter measures the voltage in the resistor. What is the resistance in the region that the current goes from 1-4 Amps? (BTW, the red line is a best fit line.) Homework...

ok so if we have an amplifier with direct negative feedback we have a voltage follower if we put a resistor between that inverting input pin and ground, we can do these things: if we put another resistor between the output and the inverting input we can adjust the gain if, instead, we...

Dumb question. Can't seem to understand how pull up resistor works when interfacing TTL to CMOS. A TTL output connected to a CMOS input. TTL output is 3.3V, but CMOS requires 5V. When TTL output is high, one end of resistor is 3.3V and the other end is 5V. The 3.3V end is connected to...

How do you find the current through a resistor that is in parallel with 2 other nonequal resistors? I totally forgot how to do this. as an example, if E = 10V R1= 5ohm R2 = 10ohm R3 = 15ohm So, I know that 1/Req = 1/R1 + 1/R2 + 1/R3 = .533ohm and also know Inet = 10V/.533ohm =...

I'm trying to use a MOSFET as a voltage controlled resistor, and am under the impression that it acts this way when it is in the linear region. However, our VDS will be 2.5V-20V, and our VGS will be 3.6V-5V. That means our VDS will most likely be greater than our VGS - VT, which means it will...

Homework Statement What current flows through resistor R1 (350 Ohms) in the figure when the applied voltage is 50 V? Homework Equations V = IR ? The Attempt at a Solution I would have thought the answer would be zero because I thought the potential at R1 is equal (but this was incorrect)...

Homework Statement Given a series circuit with a capacitor of capacitance C, a resistor of resistance R, a DC voltage source with a voltage V, and an open switch (by open I mean not connected so no current flows through). At t=0 the switch is closed. How much energy is dissapated by the...