Solving for Terminal Voltage and Current in a Battery Circuit

  • Thread starter Thread starter kbyws37
  • Start date Start date
  • Tags Tags
    Current Voltage
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
4 replies · 8K views
kbyws37
Messages
67
Reaction score
0
A battery has a terminal voltage of 12.0 V when no current flows. Its internal resistance is 2.0 Ω. If a 1.7 Ω resistor is connected across the battery terminals, what is the terminal voltage and what is the current through the 1.7 Ω resistor?


Can someone point me in the right direction?
I know I have to use V = E - Ir because there is a internal resistance.
But I am not sure how to start...

Thanks in advance.
 
Physics news on Phys.org
Treat the internal resistance as a series resistor, find the total circuit current.

What is the voltage drop across the internal resistance? What do you think that will do to the terminal voltage?
 
The terminal voltage is less than the emf because there is a voltage drop across the internal resistance.

I am still confused.
 
Last edited:
As said earlier treat internal resistance as a series resistor

net resistance= R+r = 2+1.7

current= E/R = 12/3.7

terminal voltage = E - Ir