Hello guys,

In a simple CE npn BJT circuit, is it possible to have some leakage current flowing from ground through the emitter terminal to the base IF a negative voltage is applied as input to the base?

thanks

 

Yes, the B-E junction acts like a diode, so there is reverse leakage current. In fast switching circuits high negative voltage was applied through current limiting resistors to the base to suck charge out of the junction fast. If the applied negative voltage exceeded the B-E breakdown spec the junction would zener. Later it was proved that repeated reverse breakdown caused a beta degradation.

 

Hello,

As said the reverse voltage breakdown is given in the datasheet as Veb0.
See the picture for an example:

Bertus

 

Yes, the B-E junction acts like a diode, so there is reverse leakage current. In fast switching circuits high negative voltage was applied through current limiting resistors to the base to suck charge out of the junction fast. If the applied negative voltage exceeded the B-E breakdown spec the junction would zener. Later it was proved that repeated reverse breakdown caused a beta degradation.

Thanks ramancini8 and bertus. Exactly what I wanted to know.