How Do You Calculate EMF and Potential Difference in a Circuit?

[Chandasouk]

Part A
Find the emf E1 in the circuit of the figure .
=




Part B
Find the emf E2 in the circuit of the figure.
=




Part C
Find the potential difference of point A relative to point B.

A) I wrote a KVL using the top loop. First I found out what the current going through that loop was using KCL at node A and it turned out to be -1A. My loop goes from node B to A and back to B again.

So
\epsilon₁ -(+1)(1ohm)-(+1)(4ohms)-(+1)(1ohms)-24V-(+1)(6ohms)= 0

and \epsilon₁ = 36V ?

I used +1A as my current because I am going opposite of its real direction in my KVL

 

[skeptic2]

In your equation, where did the 24V come from?

Also, how do you know the current through the 1 ohm and 4 ohm resistors is in the same direction as the current through the 1 ohm and 6 ohm resistors?

This type of problem is generally solved with simultaneous equations where one equation represents the current in one loop and the other represents the current in the other loop.

 

[Quinzio]

No, E1 is not 36V.

You can calculate Vab, so get it and the write the equation for the middle branch with E1