This CMOS circuit was found in a Popular Electronics from the 80's. The circuit consists of a counter that has its output activated when the selected key combination is pressed.
This transistor tester circuit has the advantage of using a constant current source in the tests....
This circuit is from a 1977 publication for radio amateurs presenting a crowbar protection. The...
Suggested by a 1968 documentation, this circuit limits the current of a regulator and can be...