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 amplifier for a sinusoidal function generator uses a 741 integrated circuit. The circuit is...
This circuit is from Motorola's Linear Interface ICs of 1993. The circuit can be powered by...
This circuit is from 2005 documentation. It automatically starts an irrigation pump when the...