This circuit with TTL output was found in a 1968 EEE. The transistor can be of general use. The tunnel diode is an uncommon component today.
This circuit is from a 1966 General Electric documentation. The circuit applies to sensitive SCRs for...
In the figure a circuit that is the basic application of NE567 for the detection of a tone applied to...
Found in old documentation, this circuit is the receiver for the previous circuit. Components are...