We found this circuit in an Australian publication from 1991. It is a kit of the time with input for a guitar pickup. The range is a few tens of meters.
This circuit controls two relays from a single temperature sensor. The first fires when the...
This converter converts a signal in the 200 kHz to 3.8 MHz band into frequency signals that can be...
Found in a 1980s American publication for amateur radio this circuit uses components from the era. The...