We found this circuit in a 1991 Hobbyst Electronics. The circuit makes use of an unusual transducer today. It is a piezoelectric buzzer that can eventually be replaced by an equivalent configuration.
This complementary circuit increases the output power of an operational amplifier. Outputs with...
A Popular Electronics from the 90's suggests this circuit that is based on a low voltage...
This circuit was found in Popular Electronics. Its purpose is to warn the visually impaired when a glass...