This circuit is from a Radio Electronics from October 1970. The circuit uses transistors from that era and has a low impedance output. The resistance R1 depends on the impedance of the input signal.
The integrated 4017, a C-MOS counter, is one of the most popular in the design of sequences,...
This simple very low power circuit can be used in a battery powered infrared tone trigger. We...
This timer controls two relays, each with a different timing, activated separately. The circuit is from...