This circuit was obtained in a 1982 English magazine. The purpose of this circuit is to interface signals other than TTL circuits with TTL inputs. The transistor can be a BC548, 2N2222 or any equivalent.
This configuration can be found in other articles on this site. This was obtained in 1998...
This circuit generates both white and pink noise. The transistors can be BC548 and the power...
Found in 90s Radio Electronics, this shield can control high voltage loads in the power grid....