🚀 go-pugleaf

[circuit deleted]

Icbo is collector-base leakage current with the emitter open. It is usually
specified for a 'large' collector-base voltage. It is also exponentially
related to temperature and approximately doubles every 8 degrees C (Ouch!).

Icbo is troublesome in the sense that when you connect the emitter (ie, use
the transistor in a real circuit), it will produce a collector-emitter current
approximately equal to (beta*Icbo). As collector current increases, so does
device heating, and thus Icbo, thus Ic... It is possible to construct a
circuit which will have sufficient positive thermal feedback to self-destruct.

But fortunately, you can shunt-away some/most Icb(o) by driving Vbe with
a voltage source, instead of leaving the base open. As suggested in the
original article, you can apply reverse Vbe bias without damaging the device
if you follow the spec. I did this with a 850V/75Amp (yes my friends, thats
AMPS, not mA or uA) device and its still quite healthy.

- - - 

Though possibly off-subject, unclamped inductive loads (or improperly clamped)
are the most prevalent transistor-zappers in motor/inverter circuits. Have
respect for 1/2LI^2 ;if you don't provide a path for it to dissipate, it will
transmute your expensive device into a fuse.

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