Found in Radio Electronics from the 90s, this siren finds many variations on this site. The transistor must be equipped with a heat radiator.
Found in Radio Electronics from May 1959, this transistor tester is quite sophisticated. The...
We found this circuit in a 1998 documentation. It tests common household appliances to see if they...
This filter is suggested by Motorola's Linear Interface ICs of 1993. This same configuration...