We found this circuit in Ferranti's 1974 transistor manual. The components are from the period. The table gives the value of C1 for different frequency ranges.
This circuit is from the documentation of Radio Shack 1975. It can be mounted with 12 V relays,...
Using an optocoupler this circuit turns on the light in a bedroom for a set amount of time when...
This circuit is used for remote current monitoring. In the original version of the 80s a lamp is...