Multimeter Input Protection Circuit

[tomcarlson]

I remember watching an episode several months ago, where Dave talked about how some multimeters use a BJT or a couple of BJT's as over-voltage protection in a clever, non-standard way.  Can anybody point me to the episode or help me remember the specifics of this circuit?  I seem to remember that you needed a special type of BJT as well.

[thm_w]