Found in a National Semiconductor manual, this circuit is intended for data transmission over a twisted pair, the signals being obtained from a photodiode.
In this circuit the capacitor under test is charged at switch position A and then discharged...
This is a common circuit in the 1990s, when experimental FM transmitters were in vogue. The...
Using a piezoelectric sensor of the time, this circuit was found in the February 1994 issue of...