We found this circuit in a 90s 73 magazine for radio amateurs. The circuit has 3 W of power and can use modern equivalent MOSFETs.
March 2017 - Mouser Electronics is making available the new Olimex A20 OLinuXino single board...
This operational amplifier configuration has gain controlled by an external voltage applied to a...
This circuit needs only 0.7 V at 40 uA to drive the relay. We found it in the November 1993...