That's the correct way. REF Lo is not a "ground" wire. It's an independent return path for the REF Hi signal.

Get the scope on the signal before you worry about how to smooth it out. The cheapie units actually produce a very bad sawtooth. A good battery charger combined with a noise filter can produce a...

You've probably checked, but the PC power supplies often provide a pulsed DC signal and sometimes it's not a very clean one. Many 12V components will work with this but it can introduce a fair...

The "no longer available" stimulator looks like one designed by (I think) Bob Ward? He was on thirdgen last I knew. If my memory's any good he had an old Malibu with twin blowers from a junkyard. He...