Calculating Time Constants for RC and RL Circuits | Simple Physics Homework Help

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Homework Help Overview

The discussion revolves around calculating time constants for RC and RL circuits, focusing on the application of relevant formulas for each circuit type. The original poster presents their calculations and reasoning for both circuits.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to calculate the time constants by considering the total resistance in the RC circuit and the equivalent resistance in the RL circuit. Some participants question the impact of resistor placement on the calculations.

Discussion Status

Participants have provided feedback on the original poster's calculations, with some affirming the correctness of the attempts. There is an ongoing exploration of the assumptions related to resistor placement in the circuits.

Contextual Notes

The original poster's calculations rely on specific configurations of resistors and capacitors, and there is a discussion about the implications of series and parallel arrangements on the time constant calculations.

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Homework Statement



Calculate the time constants of the following circuits

I drew them in the attachment


Homework Equations



t=RC in a RC Circuit

t= L/R in a RL Circuit







The Attempt at a Solution



Im not sure if in the first one, I would simply add the two resistors and multiply the total by the Capacitance ?

If so, then it would be 45 k Ohm x 2 Micro Farads = 45000 Ohms x 2E-6 Farads = .09 Seconds


The second one, I calculated the value of the parralell resistors as 30 ohm x 80 ohm / 110 ohm = 21.81 Ohms

Then it would just be 50 milliHenries = .05 Henries / 21.81 Ohm = .0022 Seconds
 

Attachments

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Correct.
 
For the first one, it doesn't matter that the second resistor comes after the capacitor ?
 
It doesn't matter. The resistors are in series. Whatever charges move through one resistor, have to go through the other.
 
Cool, so I was correct on both attempts ? Good News




Thanks
 

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