Bipolar Junction Transistor BJT voltage follower circuit improved to eliminate base emitter diode shift

Amplifying the power of a signal voltage using a single bipolar junction transistor BJT emitter follower circuit, either outputs approx. 0.6V lower (NPN) or approx. 0.6V higher (PNP) voltage than the signal voltage. You can easily combine a NPN and PNP BJT emitter follower circuit to counter each others voltage shift so that you output the same voltage as the signal.

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Simple NPN bipolar junction transistor BJT emitter follower set by trimpot divider schematic diagram by electronzap electronzapdotcom
Simple NPN bipolar junction transistor BJT emitter follower set by trimpot divider schematic diagram by electronzap electronzapdotcom
Simple PNP BJT emitter follower bipolar junction transistor common collector circuit schematic diagram by electronzap electronzapdotcom
Simple PNP BJT emitter follower bipolar junction transistor common collector circuit schematic diagram by electronzap electronzapdotcom

The PNP emitter voltage is 0.6V-0.7V higher than the base voltage. It’s an odd circuit though because to power a load that needs current, the load has to be on the positive side of the circuit. So, ultimately the emitter voltage is dropped from the load in relationship to Vcc (the positive supply voltage).

Combining NPN and PNP emitter follower circuits:

Vout equals Vin Bipolar Junction Transistor emitter follower common collector thanks to cascading NPN and PNP BJTs schematic diagram by electronzap
Vout equals Vin Bipolar Junction Transistor emitter follower common collector thanks to cascading NPN and PNP BJTs schematic diagram by electronzap

Cascading 2N3904 NPN 2N3906 PNP emitter followers to get voltage out almost the same as voltage in

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