This battery-powered 3-valve circuit was found in American documentation from 1947; Two batteries are used, one high voltage and one low voltage for the filaments.
Intended for SSB and CW reception, this circuit was found in old English documentation. The...
Using two transistors, the resting current for this alarm is 25uA. The circuit was found in an...
This simple rain, leak or moisture detector circuit appears in other places on this site with...