4093 Sine Square Converter (CB26335E)

Found in a Popular Electronics from the 90s, this circuit operates up to about 5 MHz input.

Dimmer (CB1592E)
Incandescent lamps, heaters and other resistive loads can be controlled by this circuit whose...
Magnetic Head Preamplifier (CB18898E)
This is a commercial circuit from a Japanese publication from 1972. The circuit uses a FET that...
117V x TTL Interface (CB24897E)
Using a 4N33 optical coupler, we have in the figure an optical interface for TRTL circuits,...