# Homework Help: Quick voltage question

1. Mar 5, 2005

### EvLer

Hi all, I am asking to see if I understand voltage correctly:
This is what circuit looks like:
Code (Text):

-----R1---A----R2---
|           +      |
Vs         v(t)    |
|           -      |
|_________B_______ |

As I see it, v(t)(voltage drop from A to B) is voltage across R2, is it correct?

2. Mar 5, 2005

### formulajoe

that is correct

3. Mar 5, 2005

### Corneo

What? the sum of the voltage drop from R1 and R2 is equal to the EMF (battery).

4. Mar 5, 2005

### EvLer

Didn't want to start another thread, but now I have another question: after the switch in some circuit moves to a certain position I get following circuit:
Code (Text):

A-------R1--------------
|        |
|        |
indctr     R2
|        |
|        |
B-----------------------

Then voltage drop from A to B is sum of voltages across R1 and inductor (or R2), right? Then there is a current coming from A and divides into 2 (for inductor and R2)? Or does R1 not have any current?
Thanks again.

Last edited: Mar 5, 2005
5. Mar 5, 2005

### formulajoe

drop from A to B is Vr1 and 2*Vr2. Even though the inductor and r2 voltages are the same, they both must be added.

6. Mar 5, 2005

### EvLer

Why 2*VR2? they are in parallel. What am I missing here? Don't inductor and R2 follow KVL?

7. Mar 5, 2005

### formulajoe

oops, my bad. youre right. its just one.

8. Mar 5, 2005

### EvLer

Oh, Ok, thanks!