Found in a 1980s manufacturer documentation, this circuit can be used as an optical shield. The integrated circuit is from the era and modern equivalents can be tried out.
This circuit was found in a Popular Electronics from the 90s. The circuit uses general purpose...
Found in Raytheon's 1960s transistor circuit manual, this circuit employs the CK722, one of the...
This encoded lock circuit with alarm for use in homes was found in a publication from the 90s. The...