Found in a 1967 Electronics World, this oscillator changes its tone when objects move in their environment. The output is made on a low impedance phone.
This Motorola circuit uses only one transistor. The circuit is from 1965 documentation. The...
This circuit uses a piezoelectric transducer to produce sounds like a buzzer. Frequency is...
This circuit was suggested by General Electric in a 1965 documentation. The circuit can be...