This circuit uses the LM2931 which is not a common component today. What it does is to activate a lamp causing it to blink at a frequency determined by the capacitor.
.
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...