Consider the following diagram, where V 1 = 14.5 V, V 2 = 10.5 V, R 1 = 86.0 m,
ID: 1531978 • Letter: C
Question
Consider the following diagram, where V1 = 14.5 V, V2 = 10.5 V, R1 = 86.0 m, and R2 = 11.0 m.
The figure shows a simplified circuit diagram for an automobile. The equivalent resistor R represents the total electrical load due to spark plugs, lights, radio, fans, starter, rear window defroster, and the like in parallel. If R = 0.800 , find the current in each branch. (Take the positive direction to be up.)
I alternator = ? (in A)
I battery = ? (in A)
I Resistor = ? (in A)
What is the terminal voltage of the battery?
Explanation / Answer
let the current in alternator is I1 (upwards)
current in battery is I2 (upwards) ,
apply KVL in alternate loop ,
14.5 - 0.086 * I1 - 0.80*(I1 + I2) = 0
0.886*I1 + 0.80*I2 = 14.5 .......eq1
aplly KVL in battery loop ,
10.5 - 0.011*I2 - 0.80*(I1 + I2) = 0
0.80*I1 + 0.811*I2 = 10.5 .......eq2
by solving eq1 and eq2,
I2 = -29.23 A
apply I2 in eq 1,
0.886*I1 - 0.80*29.23 = 14.5
I1 = 42.75 A
I alternator = 42.75 A
I battery = 29.23 A
I resistor = 42.75 - 29.23 = 13.52 A
(b)
terminal voltage of the battery = 10.5 - 29.23*0.011
Vb = 10.17 V