Resistor Definition and 879 Threads

Hi, I do not understand how the resistor affects the current in this potentiometer circuit. I asked my classmate and they said the switch is connected to the battery but I do not understand how. Why does the current increase?

Hi, I am ultimately looking to be able to have an analog circuit with an amplifier that uses a pot for the resistor over the op amp (maybe there's a better way, let me know if there is). I want to be able to control the shape of the gain roll-on/roll-off, and have it be functions of R...

I understand that removing bulb E will cause the equivalent resistor to change in the circuit. This change will cause the current across the circuit to change (which will either brighten or dim the bulbs). I found that R_eq (with E) is 1.167. R_eq = [1 + (1/1+1)]^-1 + [1 + 1]^-1 = 1.167 I...

In the Dark Ages, resistor values were indicated by colored bans, and we all had to memorize the code. (This was back when they were bigger than a speck of dust) My question is - why colored bands? Caps have numbers printed on them (as do some resistors). Why fool with bands if you can just...

I found how to get the solution to this question (the answer is 200V), but I don't understand why we ignore the 30kOhm resistor when using analysing the circuit. Because it is in series with the open voltage, wouldn't there be some voltage drop across the resistor that would affect the...

I tried splitting it up into 4 individual resistors, adding them up (each side serially and then both sides with each other as parallel) and then using V=IR but it ended up being the same current as the original. (The answer should end up being (9/8)* the original current)

I am solving #5 in the attached image. So I am graphing the power dissipated by a series circuit which : (a) Contains a constant voltage source and a variable resistor, R (b) Contains a constant current source and a variable resistor. It makes sense to me to just use the power equation that...

In this figure, I suppose the maximum voltage is when R2=1kohm and the minimum voltage is when R2=0kohm, which means R2 is a variable resistor. Is the way I think is correct or not? Please give me suggestions. Thank you.

I would think that it is 2 A (6/3 because there are three wires the current can go to), but this does not seem to be correct.

I need help with part c. My solution: Is there an other way to do this other than dimensional analysis? P.S "dr an infinitesimal radius", it ofcourse should be dz.

Greetings, fellow travelers. I gave been digging into some of my old (1970s) Electronic maths textbooks and for my amusement and time wasting refreshing some old knowledge. Have got through a fair but but have to keep coming back to this problem. I do have the answers but I cannot regardless of...

Hello guys, LRC circuits with an AC source are having the best over me... had some confusion in class with respect to which method is best using(phasors diagram, reactances or complex impedances) which I am trying to desperately sort out before my exam; here I will show you my best attempt on...

T=R/C So: 0.003s=R/100μC R=3*10^-7Ω I am really confused with the equations I have to use

On Chegg they solve for V using P=V^2/R using 36W and R1= 25Ω, which is equal to 30V then they add R1+R2 = 40Ω and they plug in P=V^2/R and solve for P which is 22.5W I'm confused on why they didn't use P=I^2*R cause you know the system is in series so I is the same and solve for I then...

The answer sheet assumes that the resistors in both circuits are in series and that we need to use the equation Req = R1+R2+R3.. to find the Req in both cases. How come the resistors are in series, when there are multiple resistors in a single row? Also, why does the following work yield the...

Summary:: How de you find the missing resistor (R6) in this problem. I assume you take the current flow of the parallel circuit to find the resistance of R6 but I feel like there is still some missing information

I'm trying to do a power analysis on my target, which runs on 3.3 volts. Without the resistor, the average current while running is roughly 140mA. I used a 10Ohm resistor as a shunt resistor with a 5V power source. The voltage difference between VCC PIN and GND was measured using a shunt...

Hello! Consider this circuit; Now the value are given as follows; U = 10V; R1 = 150 Ohm R2 = 470 Ohm R3 = 330 Ohm; I am susposed to calculate the voltage at R1 when S1 clossed;so when there is a current flowing through it. I did that using the loaded voltage divider,since I can see that R2...

Hey all, I have a 5v IC that is triggered by a sensor to unlock the 12v lock, I am using a NPN transistor as a switch with the 5v VCC as the gate, I need it to sink back to the GND of the IC without blowing it, is this safe? If not what changes would you suggest, it has been years since I've had...

I was following this problem up until they say we can they state I3= I1-I2. I understand why we can say that but I don't see how I can use that to get the system of equation in terms of I1 and I2 at the bottom. Could someone show me how this was done?

i found current to be 2/5 A. then 2/5A multipled by 6s = 2.4C. and since one joule per coulomb is equal to the unit of p.d, i get 2.4J. I don't get 4.8J(supposed answer)

In the circuit equivalent of a solar cell, shunt resistor is described as "The irregular polycrystalline lattice grain boundaries that resist to the flow of electrical current in the silicon material." If this explanation is correct, shouldn't it be "lower shunt resistance increases the current...

Also would a passive filter add much resistance to the circuit and rob the speaker of power? Here is the 2 way lowpass filter I was thinking of. I don't need 2 of these obviously but they seem to come as a pair. https://www.amazon.com.au/dp/B07R613YSK/

I am going to have several series/parallel capacitors so need balancing resistors. I understand that for series capacitors, it is wise to use voltage balancing resistors so mismatch in individual series capacitors leakage current can flow through the resistors which prevents individual...

I'm thinking I should apply Thevenin's Theorem to find the voltage, but I need to find I_D in order to be able to calculate U_S.

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Summary:: Current through a certain resistor in a mixed dc circuit. Hi, Sorry if this is the wrong forum. I'm trying to work out the current through R1.The answer I need is 2 Amp, which I have confirmed with a simulation software. I have calculated the source current as 8A, the current past...

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Summary: Why would you choose a RC with a non-inverting op-amp instead of an integrator with feedback resistor for an active LPF? I was at an interview not long ago and one of the classic questions popped up: Draw me an active LPF with gain. I've seen it plenty in my book (Sedra and Smith) and...

DISCLAIMER: don't answer in terms of integrals, I haven't covered those yet :) Hi guys, I'm having a few troubles understanding RRL circuits, and have a few questions for you. A "normal" RL circuit will have a current growing inversely exponentially, starting from 0 and going to ##V/R## as...

Since the power generated by both primary coil and secondary coil would be the same in a transformer, so I used the relationships stated above to deduce the resistance R in secondary coil. P1 = N2^2 *100 = 100^2 * 100 P2 = N1^2 *100 = 500^2 * R R = 4 Let me know if my thoughts here are...

But I think the answer is 32, is it correct?

Dear PF, I am trying to solve practice problem 8.1 and I am stuck on part b which asks us to find di(0+)/dt and dv(0+)/dt. Down below in the picture is my attempt. Before t=0 it is quite intuitive since the inductor acts as short circuit to steady-state DC and a capacitor acts as open circuit...

I wrote the following equations using node voltage, my issue is that I'm confused about why the RC branch at the output doesn't effect the value of the Gain for the amplifier; the equation involving VA / ( 20k - j12k ) is omitted in the solution. IAC = IAB + IBC V- = V+ = VB = VS ( VA-VC...

Hi, I'm reading the following paper (L. Chua) about the state-of-art of dynamic non linear circuit analysis -- Chua_Dynamic_Circuits I've a doubt about Theorem 2 on section 3.2 On the Existence of the Resistor Function that establishes sufficient conditions for the existence of network...

Having more difficulty understanding the concept, thus I am not showing values. What is causing me confusion is the line in the middle. The first aR and bR are obviously in parallel, but the second aR and bR confuse me. I tried calculating the equivalent resistance from the first aR and bR and...

So, having two parallel resistor ##R_{1}## and ##R_{2}## , the current flowing through the equivalent one will be ##I_{eq}=I_{1}+I_{2}##. Now, it comes the point I'm not totally getting: why is ##V_{eq}=V_{1}=V_{2}##? These V's are the difference of potential measured between which points...

So, I started by writing down conditions imposed by Kirchhoff's laws, coming up with a system of 3 equations with the 3 unknown currents: $$ \left\{\begin{matrix} 9V-8\Omega I_{8}+6V-4\Omega I_{4}=0 \\ 6V-4\Omega I_{4}+3V-2\Omega I_{2}=0\\ I_{2}+I_{8}=I_{4} \end{matrix}\right.$$ But...

Find the current through the 40ohms resistor using the Thevenin? I have calculated the Zth = 10 ohms. And I couldn't find the Vth.

Really very elementary one, if i refer the circuit below For the source in the direction of current the polarity is -Ve to +Ve that is understood which is conventional current, but in the case of resistance in the direction of current the voltage V_R polarity is -Ve to +Ve. Why for resistance...

I know there is a serial and parallel circuit I know R1 = 2k, R3 = 1k and i know Vout which is 1V. And i know 5V is coming from supply. I need to calculate the size of resistor R2. I can calculate : 1) IR1 = 5-1V/2000ohms = 2mA 2) UR1 = 0,002A*2000ohms=4V voltage drop on R1 How do i go on...

I understand that when sizing balancing resistors you should consider the power rating of the resistors. The resistance and power rating has to be high enough so that they do not overheat. Even with a large enough power rating, I know that they will effect your overall efficiency since that's...

1)$$R=\frac{\Delta t(\Delta V)^2}{Q}=\frac{\Delta t(\Delta V)^2}{mc\Delta T}=8.33\,\Omega$$2)$$\Delta t'=\frac{mcR\Delta T'}{(\Delta V)^2}=\frac{\Delta T'}{\Delta T}\Delta t=59.4\text{ min}$$3) I surfed the net a bit and have found a post on physics.stackexchange in which it is mentioned that...

Hi all, Checking my answers here as it doesn't seem to match with the answers given to me. Would appreciate if anyone could point out the mistakes I made. First I will compute Rth. Offing all independent sources, applying a known voltage across R (in this case 1v) and using mesh analysis...

Consider the resistor network shown in Figure 1-1, where 𝑅1=2𝑘Ω and 𝑅2=5𝑘Ω. (a) Calculate the numerical value of the single equivalent resistance, in 𝑘Ω, as seen from the terminals 𝐴−𝐴′. Express your answer to two decimal places.Next, consider the circuit shown in Figure 1-2, where 𝑉=30𝑉 and...

Hi, I have a simple question that I don't have a fundamental understanding of: do resistors dissipate reactive power (in addition to active power)? For context, when we are looking at a transformer (single phase) equivalent circuit (similar to the one in the image attached), we are asked to...

So I have these 10k 5% resistors from Stackpole Electronics and just because I never actually took the time to look at a resistor datasheet beyond nominal resistance, tolerance, and power rating specs, I decided to look them up. Came across a couple things I wanted to ask about: 1) Maximum...

Hi. Anyone knows how to calculate the Req of this circuit? n tends to infinite.

I tried to conserve the charge on the left plates of both the capacitors as intially the total charge on both is 48 and at t=t0 the total charge is 36(on c1) +4V(V is the potential across c2) so i got V=3 and then i conserved the energy Initial energy on both capacitor = final energy on both +...

Question: I first knew that this would be a series circuit setup, there the current all around the circuit would be the same. It's given that when it's a open circuit, p.d. across the output is 4000V hence the emf is therefore 4000V. When it gets connected to a load resistor, the voltage...