an electronish puzzle

In article , John Larkin wrote: [...]

Yes, you've got me there. You could preposition the emitter voltage at just below its breakdown.

This *is* starting to sound easier than stablizing the temperature.

The transistor really looks like this:

----+----/\/\/----!!-------+------ ! ! +--/\/\/-- --/\/\--+ ! \ / ! \ ----- / / ! \ \ / / ! \ ! --- / --- --- \ --- ! ! ! -----------+---------- !

As a result none of the capacitive effects will truely be at 90 degrees and the emitter current of the ideal device will actually lag the current you drive into the emitter lead.

From your earlier post I got the impression that you intended to use a single frequency. If you use a wide enough range of frequencies, the various confounding factors such as the emitter base capacitance can be estimated and removed from the results.

When you change the carrier density, the optical refractive index of a semiconductor changes. Passing a current through a junction causes the speed of light within that hunk of semiconductor to decrease. This is because the dielectric constant of the semiconductor is effected by the carriers in it. I don't see any basis on which you can assume that the emitter capacitance will not change with the zener current.

How small do you have to make them to make the non-linearities a corrupting factor in the experiment?

Use a generator with offset and amplitude controls and simplify the emitter circuit.

In article , John Larkin wrote: [...]

Cygnal makes micros that can measure there own temperature.