Very nice! But I don't see the variant which is a modification of my original schematic: base and emitter at ground? What am I missing?

Look at Q5, R6, and R7. That's your circuit in the context of a circuit which is actually turning Q5 on and off.

 

I think what gerases is asking about is connecting the base directly to the emitter.

If you do that, the transistor will be forced OFF, definitely. Forever. You would never be able to turn it ON. So a permanent connection between the base and emitter of a transistor would not be used in a practical circuit (except when testing a transistor for leakage or breakdown voltage) because it would be impossible to turn the transistor ON, so there would be no point having the transistor at all.

 

If you do that, the transistor will be forced OFF, definitely. Forever. You would never be able to turn it ON. So a permanent connection between the base and emitter of a transistor would not be used in a practical circuit (except when testing a transistor for leakage or breakdown voltage) because it would be impossible to turn the transistor ON, so there would be no point having the transistor at all.

Thanks, Chris. That's exactly what I needed. You can definitely understand the mind of an electronics newbie.

Merry Christmas, everybody!