This QST circuit generates 4 frequency signals according to the crystals used. Transistors admit equivalents although the indicated types can still be found with some ease.
The TTL 74123 integrated circuit consists of a monostable that can be configured to generate...
This constant current source from a 1980 publication can be used on a battery charger. Transistor Q1 may...
This circuit uses one of two D-type flip-flops available on an integrated circuit 4013. The...