On Sun, 05 Mar 2017 07:44:18 -0800, John Larkin wrote:

I have a clamp-on ammeter that pretty much does that, although it just
indicates amps, and doesn't allow waveform snooping. 60 Hz waveforms
aren't terribly interesting.

Indeed they're not. But your meter is presumably *only* designed for use
at 60Hz, I would imagine. Hook it up to a 100Hz signal and you'll see
nothing at all in all probability. ;-)

One can use existing switcher inductors as current shunts. I wish I had
a PCB trace current probe, but that's probably not posssible. You can
measure millivolt and microvolt drops across traces and vias.

Do they even exist? That would be amazing but no doubt *way* beyond what
I can justify to splash out on as a mere hobbyist.