Found in documentation from the 1990s, it uses a sound effects integrated circuit, the SN7677 from Texas Instruments. Unusual component these days.
The purpose of this circuit is to turn off a lamp after a few seconds or minutes depending on the...
The circuit we present is that of a good power ultrasound generator, as it uses a transistorized output...
Using the well-known 2N2646 that was popular at the time, this circuit was found in Radio...