How to make a voltage controlled switch using a BJT transistor?
Well i just want to know how to use a BJT transistor in a circuit to switch on at a particular voltage. Its for a charging circuit, i want to activate i transistor at 9 volts and the current from that to charge a 6 volt battery. I already tried putting a 9 zener diode at the base of a NPN but the turn on voltage was 16 Volts. I used a C5027R and Vbe is 7V and i am really confused with what Vbe really is.