The equivalent current-source representation for a voltage-source with open circuit voltage 12 V and internal resistance 3 ohms is

The equivalent current-source representation for a voltage-source with open circuit voltage 12 V and internal resistance 3 ohms is 

(A) a current-source of strength 4A in shunt with a resistance of 6Ω. 

(B) a current –source of strength 4A in series with a resistance of 3Ω.

(C) a current-source of strength 4A in shunt with a resistance of 3 ohms. 

(D) a current-source of strength 4A in shunt with a resistance of 36 ohms. 

Explanatory answer :

A voltage source with series resistance can be transformed to a current source in parallel with a resistance

I = V/R = 12/3 = 4A and R = 3 (given)

Ans:  a current-source of strength 4A in shunt with a resistance of 3 ohms.