Resistor Definition and 894 Threads

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 Homework EquationsThe Attempt at a Solution Power dissipated in the 2 Ohms resistor will be maximum when current is maximum .This will occur when total resistance is minimum . If I think logically then I do get the right answer . But on trying to arrive at the result...

Homework Statement Why is my calculated total resistance of the circuit higher than the resistor used in series and the theoretical total resistance? In a series circuit I used a 100Ω resistor and measured the current at 1.0v intervals from 1.0-5.0v. At 1.0v the current was 8.70mA using a 100Ω...

Homework Statement In the attached file, how do I decide which side of the resistor is positive/negative? Homework Equations N/A The Attempt at a Solution The current would go through the 6V battery starting from the positive end of the 9V battery to the negative end of the 9V battery; so my...

Homework Statement http://www.chegg.com/homework-help/questions-and-answers/problem-2-variableh-resistor-r-circuit-fig-p224-adjusted-va-equals-60-v-find-value-r-q8083343 Homework EquationsThe Attempt at a Solution Hi, I attached a pdf file with the problem. My question is, for the lower right...

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 EquationsThe Attempt at a Solution I have done the definite integral and have...

Homework Statement Is a charge different upon its exit versus its entry into the lightbulb? Homework Equations PE = Vq The Attempt at a Solution Well, the answer is that the charge stays the same. Based on the equation above, since energy certainly gets reduced V must drop but I don't...

I have wired in series: + of 9V battery --- + of 1000 uF capacitor --- 660 Ohm resistor --- + of a green LED --- - of the 9V battery. Remark: the 9V battery is a bit depleted 7.8 V unconnected. Voltage drop across the capactor is 6.5V, across the LED is 1.5V but 0V across the resistor. Why...

Homework Statement Homework Equations I = VR Series = current the same, voltage different Parallel = current different, voltage the sameThe 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 In Fig. 27-66, R1= 10.0 kΩ, R2 = 15.0 kΩ, C = 0.400 µF, and the ideal battery has emf E = 20.0 V. First, the switch is closed a long time so that the steady state is reached. Then the switch is opened at time t = 0. What is the current in resistor 2 at t = 4.00 ms? This is...

Hi, I've got a small physics problem : build an thermometer using the Wheatstone bridge, only knowing the voltage and the middle resistor of the bridge. I need help for the resistors values ; I've finished the rest, which is the relation between temperature and the resistors and the voltage. I...

Homework Statement Homework Equations P = I*V energy dissipated = wr = ∫ ( P *dt) ... t is from 0 to .4 seconds vs = 400t^2 = 400 * (.4^2) = 64 V The Attempt at a Solution Using KVL I said Vs ( 64 V) = 100 * i ... I found that I was 64/100 = .64 amps. I then said power is .64 amps ^ 2 *...

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...

I want to know why in this problem in the solution, he disregarded the 1 ohm resistor and found the equivalent resistance of 6 and 3 ohms right away. https://imgur.com/a/efG11

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...

If I have a resistor and a voltage source in series but then I apply a short circuit in parallel to both of them would the voltage source and resistor not receive 0 V? Thus having 0 current. What would change in the circuit?

Greeting . It is clear to me that the resistor represents a physical obstruction to the passing current I do not know how exactly it works and I will try to show what I was really interested in the diagram.

As a quick and dirty/cheap solution, can a resistor be used instead of a step-down transformer ( stepping down from 230V AC mains to 3 V AC) to drive some simple electronic circuit such as a few LEDs or transistor radio etc ?

Homework Statement My problem is that I don't know how to deal with this kind of questions. Homework Equations V=I*R[/B]The Attempt at a Solution I thought that the overall resistance would increase since there is a hindrance after the lamp doesn't function anymore, but don't know what to...

Homework Statement Consider a circuit that consists on a resistor of an intrinsic semiconductor R and a capacitor C in series. The voltage between the terminals of the circuit is U, which is an alternated sinusoidal voltage. U1, which is the voltage in the capacitor as a phase difference of 30...

Homework Statement In an AC circuit of periodic current we know: ##E=6[V]##, ##R_g=50[Ω]##, ##L_g=\sqrt3 [nH]## and ##ω=50*10^9[s^{-1}]##. Calculate: a) All available power of the ##E## b) The resistance of ##R## so that the average power is max c) That average power from part b) Homework...

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...

Relevant equations: V=IR Attempt at solution: When the switches are open, R1, R2 and R3 are in series so the current in that case would be 12 V/ (2 ohms + 3 ohms + 3 ohms) = 1.5 A. When the switches are closed, the current across R3 is still 1.5 A, so the voltage drop across R3 is 1.5 A * 3...

Homework Statement Homework EquationsThe Attempt at a Solution Can someone tell me what formula to use? Is it p=RA/L? but what about the mass? Thanks~

Hello , I have to teach a group of 9th grade students role of resistor in a circuit and how it affects the current in the circuit . This will be their first exposition to circuits .So I need a good and simple analogy so that students can grasp these concepts easily . This is what I plan to...

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...

Homework Statement Homework EquationsThe Attempt at a Solution [/B] The first and foremost thing which I do not understand in this question is that there are many resistors present in the circuit , so how is it that we could relate power dissipated in one resistor to the power supplied by...

hi, I am am hoping someone maybe able to help me identify a resistor the middle is slighty ( fell off) from heat i suspect i will add photos the only coulors left are very end cream then a gold band then cream then middle no there any more then we have a dark brown band then light brown hope...

How would you justify the above question? Please elaborate in detail with diagrams (if applicable). It will be really helpful. Thank you.

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...

Hi there, The problem asks me to calculate the Voltage, Current and Power of each component within the circuit. I have already calculated the following: V total = 12 Volts R total = 259.54 Ohm I total = 0.046 Amps I am confused as to how I am supposed to calculate the voltage drop across each...

Homework Statement Homework Equations ##V = IR## ##\sum_{k = 0}^{n} I_k = 0## The Attempt at a Solution [/B] I set the bottom node as the reference node and worked from there to find the three equations for the loop. When I try to eliminate ##I_4## by using ##I_4 = I_2 - I_3## I run into...

Homework Statement I have a 560 ohm gate resistor on an IGBT. Usually an IGBT doesn't require a gate resistor as it already has a high impedance of its own, but I'm told that for switching applications a gate resistor can be beneficial. The attempt at a solution If there is a gate resistor...

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

Hi, I was doing some test with the load bank today and I obtain a value which I don't quite understand. I supply a 400V Line to Line, 50Hz to a smart meter and to the resistor load bank. The measured value by the smart meter was 500W and -40Var with a current of 0.71A. As the current increases...

Homework Statement Determine the voltage drop and current through each resistor. *This is just my sketch of the problem since I couldn't take a clear picture of it. Homework Equations Ohm's law V= IR Parallel total resistance Req=1/R1+1/R2+1/R3+... Series total resistance Req=R1+R2+R3+...

Homework Statement Attached to this thread is the question and mark scheme. Homework EquationsThe Attempt at a Solution I got most of the question right but I have no idea about the explanation part of why to include the 100 ohm resistor which is required for the higher level. It says in the...

Homework Statement Homework Equations / 3. The Attempt at a Solution Looking to solve mistakes to study from homework. Here's what I had so far[/B]

Helo, I am in an electronic course and we just started studying diodes. I am stuck on the following problem: Place a 100 ohm resistance in series with a diode, and plot current versus voltage across the series combination. I am also given the following values for the diode: n = 1, Is =...

Homework Statement Referring to the diagrams below, what would a suitable value for Rg and why? I have did a lot of research and can't get a clear answer, can someone clear it up for me?

Homework Statement You must complete the circuit of (Figure 1) in such a way that it draws a current of 0.450 A from the battery. The battery maintains a potential difference of 10.0 V with no load, but has an internal resistance of Rbatt = 15.0 Ω . The only material you have is 20.0 mm^3 of...

Why does capacitor charges up to full voltage as the emf of the battery even if there is a resistor is connected in series? I know that having a resistor means it will take longer to charge the capacitor but shouldn't some energy need to be lost in the resistor as well?

Homework Statement A resistor connected across an AC power supply has a current given by I=(1.35A)cos(300t) when connected to a power supply with emf 120 V rms. Find the RMS current. Homework Equations IRMS=Imax/√2 The Attempt at a Solution IRMS=Imax/√2 IRMS=0.477 A INCORRECT Not exactly sure...

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 finding the resistor and current which is following through the circuit[/B]Homework Equations kirchhoff law The Attempt at a Solution almost as fig 1 ( 9v=3.458 mA and 12v=11.122 mA) fig 2 (9v=1.472 mA and 12v=12.882 mA) i3=2.48 mA