Found in documentation from the 1990s, it uses a sound effects integrated circuit, the SN7677 from Texas Instruments. Unusual component these days.
This circuit was developed to test suspect 4001 and 4011 integrated circuits. The circuit is from...
The power source shown for powering for small TTL circuits was found on a Radio Electronics...
This circuit was found in a Popular Electronics from April 1993. It is a voltage regulator circuit...