This small signal amplifier circuit was found in Motorola's 1969 documentation. The FET and the transistor can be of any type and is battery powered since the consumption is very low.
This setting appears with variations at various points on this site. This is from a Motorola...
This circuit indicates through LEDs when an automotive fuse is open. ...
The circuit shown in the figure generates a rectangular signal whose frequency depends on C1. For...