This high input impedance circuit is suggested by Motorola's 1993 Linear Interface ICs. The power supply must be symmetrical. The circuit has a differential input.
This circuit is from Popular Electronics from the 90's. The circuit discharges the battery with a...
We found this time base circuit in a timer project from the August 1972 Radio Electronics...
This sonic switch, vox or sonic relay uses a Darlington of the time that has a gain of 10,000. The...