In a Thevenin circuit with V_th = 12 V and R_th = 2 Ω feeding a short-circuited load (0 Ω), what is the current through the source immediately after connection?

In a Thevenin circuit with V_th = 12 V and R_th = 2 Ω feeding a short-circuited load (0 Ω), what is the current through the source immediately after connection?

• A. 0 A
• B. 6 A
• C. 12 A
• D. 3 A

Answer: (B)

When the load is shorted, the current is the short-circuit current, set by the Thevenin resistance only. You have a 12 V source in series with 2 Ω, so the current is I = V_th / R_th = 12 V / 2 Ω = 6 A. The current travels from the positive terminal, through the short, back to the source. This is the maximum current the Thevenin circuit can deliver with that internal resistance.

When the load is shorted, the current is the short-circuit current, set by the Thevenin resistance only. You have a 12 V source in series with 2 Ω, so the current is I = V_th / R_th = 12 V / 2 Ω = 6 A. The current travels from the positive terminal, through the short, back to the source. This is the maximum current the Thevenin circuit can deliver with that internal resistance.