A useful addition to your toolkit

We don't believe it until there are pictures.

I'm not sure I can name names yet. It's still in development.

We've become sort of a beta tester for these people. They send us units and get our feedback, and we can keep them. Or maybe they just like coming to San Francisco.

I used to like using a Tek Hall sensor probe. I liked it checking DC shorts on boards.

Greg

Yes, but have you seen the prices? The cheapest model that does DC is $1,600.

I rolled my own. I took an old Honeywell SS495A Hall effect sensor, built a suitable amplifier, hot melt glued it to a piece of plastic, and calibrated it by shoving DC through various PCB traces. It's ugly, not very sensitive (3mv/gauss or 30uV/uT), and goes nuts near magnetic fields from xformers, inductors, steel mounting brackets, wall warts, etc. However, it's cheap and easy. I don't use it for troubleshooting very often.

The original suggestion sounds much like an RF current probe. However, these cannot be used to measure current though a PCB trace.

Oh come along now. You know it's not intended for that sort of usage!

Unlikely. ;->

I was using a NASA owned probe. Thought about trying to make one.

Greg

I ordered one from Newark, and plan to use it on my messed-up switching power-supply designs. Qualitative results will be fine.

Mine arrived today. I plan to monitor fuel injection impulses with it firstly just to see what kind of di/dt responses it's capable of. I'm not quite as confident as you are, though!

I do a lot of fast HV pulsing circuitry, and don't expect it'll be helpful for that kind of work. But the 5MHz bandwidth should be fine for looking at inductor current ramps, cap charge-discharge, etc.

a few years back there was talk of using a video head from a VCR (after removing it from the drum) to probe AC currents. It should be good to a few megahertz. a core from an ethernet transformer with a gap added could be another option. a spool-shaped inductor would probably work too.

A little unshielded drum-core inductor is a handy h-field probe.

Maybe they could not find any flowers :

Sorry I did not get the studio version, but this one looks interesting.

But I hate to say it, you will never catch me dead anywhere in California. Maybe fifty years ago but not today, even if I could afford the rents there.

You just described that PCB trace current probe; just use known trace length - with known width you get approximate current.

I do that. But multi-layer power pours are not such well-defined resistors.

Certainly did!

It all seemed to go t*ts-up right at the dog-end of 1969, around the time of the Alta Mont free concert and that awful business involving Charlie Manson and his 'Family' - and never recovered. :(

I once asked if a discarded head from an old, old hard disk could do that.

There used to be a four-pin probe for PCB current measurement, in the late 80s, but I can't find it. They're probably on ebay but I don't know what name to search for.

There's one on ebay now for $750.