- #1
greg_rack
Gold Member
- 363
- 79
- Homework Statement
- Determine the current flowing through the circuit(attached below) immediately after having closed the switch.
Values of ##V##, ##R_1##, ##R_2## and ##L## are given.
- Relevant Equations
- Ohm's law
Inductance
DISCLAIMER: don't answer in terms of integrals, I haven't covered those yet :)
![Schermata 2021-03-08 alle 16.10.22.png Schermata 2021-03-08 alle 16.10.22.png](https://www.physicsforums.com/data/attachments/262/262535-b2a055becce51608e67d27e60cee3904.jpg)
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 predicted by Ohm's law.
First question: why, intuitively(not algebraically, I know that in order to demonstrate it we must solve a differential equation), is that true?
Then, coming back to our RRL, should we consider the current flowing through ##R_1##, immediately after closing the circuit, to be ##I=\frac{V}{R_1+R_2}## with regards to the consideration above for an RL circuit, by which we deduce that the current at ##t\approx 0## flowing in the branch with the inductor, is ##I_i\approx 0##?
![Schermata 2021-03-08 alle 16.10.22.png Schermata 2021-03-08 alle 16.10.22.png](https://www.physicsforums.com/data/attachments/262/262535-b2a055becce51608e67d27e60cee3904.jpg)
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 predicted by Ohm's law.
First question: why, intuitively(not algebraically, I know that in order to demonstrate it we must solve a differential equation), is that true?
Then, coming back to our RRL, should we consider the current flowing through ##R_1##, immediately after closing the circuit, to be ##I=\frac{V}{R_1+R_2}## with regards to the consideration above for an RL circuit, by which we deduce that the current at ##t\approx 0## flowing in the branch with the inductor, is ##I_i\approx 0##?