[Amps] Grid Protection Circuit Ideas

[Tom W8JI]

> I was told to use a circuit similar to the one in the
> Ameritron AL-800 or 1200 which uses an op amp.  The
> manuals are available on the Ameritron site but do not
> contain schematics.  Any suggestions or assistance
> will be much appreciated.

Get a regular manual and you also should get the schematic.

I'd just order the PC board from them. It uses an op amp 
driving a fast relay, and by changing only one resistor 
value you can set the toggle voltage to almost anything you 
like, so it will work with almost any meter shunt.