A lady gave me this thing her husband made-he was into ham radio.It's a metal box with a power cord and 2 lugs on the side for wires.On top of the box are a rocker switch,red and green lights,and what looks like a typical 4 pin mike socket.Inside the box are a transformer,12V mechanical relay,and a small circuit board with 4 big diodes.It's obviously some sort of power supply but I can't figure out what it would be used for.Anybody know what it is?