Consider the following diagram, where V 1 = 13.0 V, V 2 = 9.5 V, R 1 = 72.0 m ?
ID: 2277632 • Letter: C
Question
Consider the following diagram, where V1 = 13.0 V, V2 = 9.5 V, R1 = 72.0 m?, and R2 = 14.0 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.)
Explanation / Answer
Ir = Ib + Ia
voltatage drop across battery = voltage drop across alternator = voltage drop acroos resistor
=> V2 - R2*Ib = V1 - R1*Ia = Ir*R
=> 9.5 - 0.014*Ib = 13 - .072*Ia = Ir*0.8
putting Ir = Ib + Ia and simplifying with first two eqaution respectively we get
9.5 = 0.8Ia + 0.786Ib
13 = 0.8Ib + 0.728Ia
solving Ia = -38.61 amp ;Ib= 51.39 amp
hence Ir = 12.78 amp
terminal voltage of battery = 13 - 0.72 =12.28 V