[Dhananjay Gadre] happened across a useful little trick the other day. Take any old 1N4148 or 1N914 glass-package signal diode and wire it up right, and you’ve got yourself a nifty little IR detector.

A subject rarely found in circuit design textbooks is the matter of nonlinear junction capacitance, especially reverse-bias junction capacitance, also called depletion capacitance. When it is ...