Circuit is shown in attachement. At t = 0s, switch S is closed. Find a function for the current through the inductor starting from t = 0s.(adsbygoogle = window.adsbygoogle || []).push({});

Using Kirchoff's method, I find that the maximum current through the inductor is .500 A as t approaches infinite and that the total current is 1.50 A. I took in the assumption that from t = 0s and onward, the current through the path with the inductor is proportionally 1/3 of the total current. Then I set up an equation:

E - 3IR1 - IR2 - L*dI/dt = 0, in which E is the emf of the battery, I is the current through the inductor, R1 is the resistor on the top left (4.00 Ohm), R2 is the resistor on the top right (8.00 Ohm), L is the inductance, and dI/dt is a derivative of the current. R1 carries the total current, so its current would be 3 times the current in R2. Using this equation, I set up a differential equation, receiving:

I = .500*(1 - e^(-20t)), in which the maximum current corresponds to the maximum current I got from Kirchoff's method.

However, the answer I'm supposed to get is I = .500*(1 - e^(-10t))...I didn't see anything wrong in my method. Any help?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: RL Circuit

**Physics Forums | Science Articles, Homework Help, Discussion**