Resistor Definition and 879 Threads

Homework Statement [/B] My question is regarding part C of the question. Homework Equations V = IR V(t) = V(1-e^(-t/tau)) The Attempt at a Solution My idea is to use Kirchoff's Voltage Law and find the voltage of the capacitor as a function of time, then since the voltage across capacitor is...

Homework Statement On the circuit I've drawn up, how do I calculate a current limiting resistor for the gate of the IGBT? The IGBT being used is a stgp6nc60hd. Also, how would I go about choosing a flyback diode for the motor?

Homework Statement Two resistors are connected in parallel. The total resistance of the combination is 6.0 ohms. If one of the resistors is 10 ohms, what is the value of the other? Homework Equations 1/RT= 1/R1+1/R2 The Attempt at a Solution I got 15 just by doing trial and error, and I'm...

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...

<< Mentor Note -- Two threads merged into one >>[/color] As a project I have to design a switching circuit for a switched reluctance motor. I've picked all the components I need and I've tried to design the circuit. Open collector - 74LS06N Optocoupler - TLP 251 IGBT - stgp6nc60hd Does the...

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...

We kept getting some voltage spikes back into our amplifier. One of the things we put in place is a 10kOhm resistor (discharge load) connected to the output of the amplifier. However, the resistor keeps burning and setting on fire. The amp company offered a way on checking this... I'm really...

Homework Statement I was reading in my physics book about loop currents. However, some resistors are added to the result (R*I) whereas some resistors are subtracted from the result -(R*I). The book uses the phrase "uphill" and "downhill" to describe this, and, indeed, the so called "uphill"...

Homework Statement A shunt-wound DC motor with the field coils and rotor connected in parallel (see the figure) (Figure 1) operates from a 140 V DC power line. The resistance of the field windings, Rf, is 248 Ω . The resistance of the rotor, Rr, is 4.40 Ω . When the motor is running, the...

Homework Statement So I was studying an example and the picture given simply asked to setup a voltage divider for the values without solving for resistance. However... I want to know if I'm missing something or if this can even be solved: I attached the problem below. Homework Equations...

Hi, In general 1/2 watt resistors is what I see in tube guitar amps. I built one with 1 watt resistors and can not hear any difference. I assume shot noise will decrease with larger wattage values. Other than heat dissipation, how is a 1 watt resistor different from a 1/2 watt resistor...

Homework Statement Find the current across 5 ohm resistor Homework Equations Superposition theorem. Other voltage sources become short circuit and current sources become open circuit. Ohm's law. I = V / R The Attempt at a Solution Using superposition theorem, we get: When only left side 10...

Homework Statement We have a resistor grid with 6x6 squres. ( figure below) If we know the voltage between ##O## and ##A##, what is the voltage between: ##a) O## and ##B## ##b) C## and ##D## ##c) E## and ##F## Every side has the same resistance. Attempt for solution: Because of the symmetry...

Homework Statement A battery with = 12.0 V and internal resistance r = 1.0 Ω is connected to two 6.9 kΩ resistors in series. An ammeter of internal resistance 0.50 Ω measures the current, and at the same time a voltmeter with internal resistance 10.0 kΩ measures the voltage across one of the...

Hi I couldn't find of these exist anywhere. Is there a component that is a variable resistor that adjusts based solely on receiving an up/down signal? And maintains its state on powerdown? I don't want this solution to involve any type of software, just a hardware solution. Looking for...

Hey! I have a question and a drew up a diagram to help out. I drew up a circuit that includes just a voltage source and a resistor. I know the voltage is constant in each of the circled portions of the circuit. As in, as you move through the wiring, the voltage doesn't change from one point to...

Homework Statement A battery of EMF 12.6 V and internal resistance 0.1 Ω is being charged from a DC source of EMF 24.0 V and internal resistance 1.0 Ω using the circuit shown in the figure below. V1 and V2 are high resistance voltmeters and R is a fixed resistor. (a) What is the polarity of...

Homework Statement Consider a thermally insulated resistor with resistance R=20 Ω and mass m=5.0 g. The resistor is made of a material with specific heat capacity c=850 J/(g-K) and carries a current of 2.0 A for a time period of 1.0 s. a) Calculate the increase in the temperature of the...

Homework Statement I am given this circuit...

Homework Statement A battery of internal resistance 0.50 Ω is connected (as shown below) through a switch S to a resistor X, which is initially at 0 °C. When S is closed, the voltmeter reading falls immediated from 12.0 V to 10.0 V. The reading then rises gradually to a steady value of 10.5 V...

Homework Statement A semiconductor diode and a resistor of constant resistance are connected in some way inside a box having two external terminals, as shown in the diagram below. When potential difference of 1.0 V is applied across the terminals the ammeter reads 25 mA. If the same potential...

Homework Statement The problem is to find the current in the 25 ohm resistor (left side) http://imgur.com/a/luKCW [Image inserted by moderator] Homework Equations KCL KVL ohms law (v=IR) The Attempt at a Solution My attempt at the solution was to add both power sources together (-5v(-5v...

Homework Statement I'm studying for a test and since this is technically a textbook problem I figured I'd post here to prevent being flagged. I have the circuit redrawn. Homework Equations Series: Req = R1+R2... Parallel: 1/Req= 1/R1 + 1/R2... The Attempt at a Solution I want to understand...

Homework Statement A current ## I=0.2 A ## flows in a resistor ##R = 50 Ω## immersed in a rigid adiabatic vessel that contains ##n=3## moles of Helium. The initial temperature of the system is ##T_0 = 27 °C##. The resistor has a mass ## m = 10 g## and specific heat ## c = 0.2 (cal/K)/g ##...

Here is an image with information: https://i.snag.gy/UMCRig.jpg I have calculated the total power dissipation as 11W. What I don't see is why R1 has a higher dissipation rate than R2/R3, and my main question is how do I calculate the power dissipation of R1? I get that R2/R3 are in series so...

1. The problem statement, all variables and given/known data Homework Equations I3 + I1= I2The Attempt at a Solution [/B]

Homework Statement For the circuit shown below the 20-ohm resistor is immersed in water surrounded by insulating foam; the equivalent resistance through the circuit is 40 ohms. The current through it is 0.75A. What is the power dissipated through the 20 ohm resistor? Homework Equations $$...

[Note by mentor: this post does not use the homework template because it was originally posted in a non-homework forum.] --------------------------------------------- Problem: What is the average power dissipated by a 25-Ω resistor in an LRC series ac circuit for which the power factor is...

If an amplifier (audio or RF) has the collector of a transistor for its output electrode and assuming the transistor operates in its active region (not saturated or cut off) the output impedance of the amplifier will be high (several 10s of kilohms). If now a tuned circuit is connected as a load...

Hi Guys, I am looking for a high level overview concerning resistor noise and how to reduce it. I have read the following general statements. Carbon comp resistors are rated at 0 db. I read this somewhere. Vishay metal film resistors MIL-R-10506 are rated at -40 db...

Question is in image included So, I need to find R2, R3, and Is. I was able to get the correct answer for R3 by doing R3= V/I (R3= 12/1 = 12) . however when I apply that equation to R2 ; R2= V/I. (R2=12/4 =3), I do not get the correct answer. The answer is supposed to equal 4 ohms. Am I using...

Hi folks, so here's my recent problem, My car has a broken MAF (mass airflow sensor) the semiconductor innards are ok but the very thin metal strip that comes into the airflow tube has become brittle from old age and broken up. I know the MAF works when it sends a low voltage through the...

Homework Statement Three resistors are connected as shown in the diagram. If the current from the power supply is 250 mA and the current through R3 is 54 mA, what is the resistance of R3? Homework Equations 1/Req= 1/R1 + 1/R2 +1/R3 V=IR The Attempt at a Solution First I used the parallel...

Homework Statement Given v0 c1c2 r1 need to find the current on r1 picture switch 1 is closed for long time and on t=0 opened and switch 2 is closed Homework EquationsThe Attempt at a Solution in the attached file i was trying to use kvl assuming that q0(charge on cap before opening switch...

Homework Statement An 11 kV motor is fed by cables from a transformer via switchgear, having a phase impedance of 0.3 + j0.3 ohm. The Earth return path to the transformer neutral has a resistance of 0.42 ohm. Determine a suitable value of neutral resistance if the voltage rise at the motor in...

Hi, I have this IC Datasheet: http://www.ti.com/lit/ds/schs015c/schs015c.pdf I need a pull down resistor at one of the input pins but I am not sure what value to use. How can I calculate what value resistor I need ?, can someone give me a specific range ?

I need to graph the current energy on a resistor, capacitor and inductor they are all separate it is not a RLC circuit. This is what I know u(t) = sqrt(2)*220*sin(314*t+π/3) R = 10 Ω L = 3 mH C= 3 mF I have already calculated the current for each component, now I need to calculate the energy...

Homework Statement I need to get 7 equations to make a 7x7 matrix in order to solve it. I have 4 of them, but I'm not sure how to get the voltages equations. Homework EquationsThe Attempt at a Solution I have got four equations so far. One is simply using KCL, I1 = I2 + I3 + I4. The other...

(sorry, I couldn't figure out how to insert an image from my drive) I have a problem where in finding the thevenin resistance I take out my independent sources and as a result I'm left with a resistor parallel to a short circuit. Should I ignore this resistor when calculating equivalent...

Homework Statement Find the current through and power dissipated by each resistor Homework Equations V=I/R ΣIin=∑Iout The Attempt at a Solution Did I set up the loop laws correctly and where do I go from here?

Homework Statement A circuit is arranged like above. To make the energy absorbed by the 6 ohm resistor every second is 1.5 J, voltage X should be ... Volt Homework Equations V = IRThe Attempt at a Solution [/B] I really have no idea. I just know that it's kinda like wheatstone bridge and...

Homework Statement The circuit [http://tinypic.com/r/2cwl7bt/9] shows a battery connected across a uniform resistor R0. A sliding contact can move across the resistor from x = 0 at the left to x = 10 cm at the right. Find an expression for the power dissipated in the resistor R as a function...

I'd like to find Vth by mesh current analysis. Mesh A and B share a current source, so they're treated as one supermesh. What's the equation for this supermesh? Also, do I ignore the loop with the open circuit? Since there's no current flowing there... 2A = ib - ia Anyway, is this the right...

Homework Statement Assume an ideal diode with ##V_t=0.6##v, find the potential differences across the diode V_ab and across the resistor V_bc as the forward bias voltage is varied from 0 to 10v. Hint: equivalent circuits may be useful Embedding the image wasn't working so...

I guess there's a simple rule, but I can't find it anywhere and it seems I was supposed to know this. I'll appreciate it if someone explains me how it works and also if (and how) is related to the way you consider positive and negative voltages when you apply Kirchoff's second law as shown in...

Homework Statement Two 1.80 V batteries—with their positive terminals in the same direction—are inserted in series into the barrel of a flashlight. One battery has an internal resistance of R1 = 0.280Ω, the other an internal resistance of R2 = 0.155Ω. When the switch is closed, a current of...

Homework Statement My question relating to physics and electric circuits, is "If a circuit consists of a 12 volt battery and two ohm resistors connected in series, then how many Coulombs pass through each resistor in a second". Thank you all so very much. Homework Equations V=IR The Attempt...