Thank you for helping!! As I work through these and verify the answers, I'm feeling more confident about being able to work these problems on the exam.
a) Use KVL method to find out current generated from 4V battery
b) Find out current passing resistor R3
c) Find out current passing resistor R1
d) Find out voltage at location “A”
e) What is power generated by 1V battery?
?
Assume that the top ends of R2 and R1 are + and the left end of R3 is +. Then
A + 1 = (I R3)(100) note A +1 is the voltage across R3
A = ( I R1)(400) Voltage A is equal to the voltage across R1
I R1 = - 1/400 + (1/4)(I R3) combining the two top equations
4 volt = (I R2)(200) + A Note I R2 is also I battery
finally I R2 = I R1 + I R3
I R2 = -1/400 + (5/4) (I R3) = -0.0025 +1.25 (I R3)
4 volts = (200)( I R2) - 1 Volt + 100 (I R3)
5 volts = (200)(-1/400 + 5/4(I R3)) + 100 ( I R3)
5 volts = - 0.5 + 350(I R3)
I R3 = 5.50 volt/350 = 0.0157 amps this is R3's current
I R2 = I battery = - 0.0025 + 1.25(I R3) = 0.0171 amps, this is the 4 volt battery current
A = 4 volts - 200( I R2) = 4 -200(0.0171)= 0.58 volts
I R1 = I R2 - I R3 = 0.0014 amps this is R1's current
The 1 volt battery current is 0.0157 amps
so its supplying 0.0157 watts