A useful addition to your toolkit

Or the modern equivalent

That promo shot looks terrible.

We have one of those. Great tool when we can't get chamber time. ;-)

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

What did it set you back?

Cheers

Phil Hobbs

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.

Yes, looks really expensive.

Not sure, I would guess somewhere in the lower 5 figures range. That's what it was ~10 years back when the support box was the size of a de sktop PC and you would need a specific spectrum analyser with GPIB interfac e along side. My old office was a short drive from their location, so we ne ver bought one but used them as consultants. :) Once the device showed us a standing wave of a higher harmonic of a clock o n a FFC. A really great debugging tool. Cheers, - Wolfgang.

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.

Dunno. I think it was bought before I was hired (5 years).

I think that's about right ($20K-$30K). A mere bag of shells compared to a lot of other EMI tools (ever price out a 3M chamber? ;-). Well worth the money.

Can you still get disclosing fluid? It was a paramagnetic liquid, usually in a spraybottle, that indicates field. Used on mag tape (or floppies) it tells you whether your eight-track tape recorder is firing on all eight tracks.

Kyread is the brand I've used. It evaporates and leaves no residue.

I think it's a fluid-in -fluid suspension, and droplets elongate in response to field strength and direction.

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.

Huh? "Bulk magnetic field viewing film, 9in. x 7.2in. Can be cut up into student sizes for the whole class to explore magnetic fields. Or use it in a complete sheet to see an entire magnet's field lines."

Those must be small students... :-)

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.