This circuit doubles the frequency of signals from 10 to 50 MHz. We found it in a 1969 Electronic Design. The components are from the period.
This circuit was found in old American documentation. Transistor is general purpose and relay is...
This simple alarm with latching uses a relay as the main element. The circuit is from a Radio...
This circuit is from an Italian publication called Fare Elettronica from 1987. What we have is an...