This signal injector and tracer (follower) was found in an old American documentation. The transistors can be general use and power is made with one or two common cells.
Epson SG 8018 Epson Crystal Programmable Oscillators Available from Mouser Electronics, these...
This circuit was found in a 1975 filter cookbook. The operational may be others, but they should...
This circuit was obtained from an English magazine from 1976. The circuit operates two LEDs and...