Howard Winter wrote:

>> My first attempt used a single floating transistor but this (stupidly)
>> included the base drive in the lower divider resistor. Usually that's
>> reasonably irrelevant. Here it's fatal. So I now have two transistors
>> in a classic bipolar high side drive.
> 
> Are you going to publish the circuit, for those of us lacking in
> classical education?  :-)  To my rather simplistic understanding, Gain
> (Beta) is Collector current / Base current.  To get this < 1, Ic must be
> less than Ib.  Where does the "extra" Base current go?  

In such a circuit, usually both the base current and the collector current
flow into the emitter.

Gerhard

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