This optical counter was found in a 1964 Electronics Design. It makes use of an uncommon optocoupler today, using emission lamp and a phototransistor.
This circuit is from a 1968 publication. It uses germanium transistors from the time, having...
This circuit can be used as shield or to drive powerful loads from low current switches such as...
This is a 6-transistor transistor receiver manufactured in the 60s. The circuit is a...