Power Transistor

Connect negative terminal of a 3-volt power source (equivalent to 2 flashlight batteries connected in series) to terminal No. 2 of power transistor. Check for continuity between terminals No. 2 and 3 with positive terminal of power source connected to terminal No. 1. See Figure. If continuity exists only when 3 volts is applied, power transistor is okay. If continuity does not exist, replace power transistor