Found in American documentation from 1968, this circuit has an acute cut-off of the frequency to which it is tuned and which depends on RC. Transistors may be modern equivalents of general use.
This circuit was obtained from Popular Electronics from March 1967. The transistor used is from...
The purpose of this circuit is to control the high and low light of a car, detecting when a...
This circuit triggers three incandescent light bulbs following the audio signal applied to its...