This circuit that imitates the sound of the cowboys' calls with their “louder” was found in a Hands On Electronics from the 80's. The integrated circuits used are from that time.
This voice scrambler is used to obtain effects in the 2.5 to 5 kHz range. The circuit is from...
This PWM circuit was found in an American publication from 1978. It consists of a simple control that...
This circuit is from a 1953 publication, consisting of an AM radio with 3 germanium transistors that,...