Hi,
I'm repairing electronics that has npn transistor as voltage regulator. The circuit is resistor from transistor collector to base and Zener diode from base to gnd. The input voltage at collector is 20V. The problem I have is that there is no voltage at output. At transistor base is 0V, I expect 12 because Zener is 12V. I replaced resistor R4P and Zener diode D9P jet no voltage at base.
I'm attaching image sorry for poor quality.
I can't figure out why there is no voltage at base?
I'm repairing electronics that has npn transistor as voltage regulator. The circuit is resistor from transistor collector to base and Zener diode from base to gnd. The input voltage at collector is 20V. The problem I have is that there is no voltage at output. At transistor base is 0V, I expect 12 because Zener is 12V. I replaced resistor R4P and Zener diode D9P jet no voltage at base.
I'm attaching image sorry for poor quality.
I can't figure out why there is no voltage at base?