Found in Popular Electronics from the 1980s, this circuit uses two operational amplifiers from that time. The circuit has frequency and symmetry adjustment.
This windshield wiper timer was obtained in an 80's Hands On. The transistor can be the BC548 and...
This circuit was found in a 1977 documentation. It limits the voltage from a source using zener...
This simple circuit found in an American 80's documentation simply blames if there are toxic gases in...