I would like a current clamp but I’m looking for something that size. I might get an old unit just for the clamp.

I have seen some on ebay for around $50 but if I were going to spend that much I'd probably get a different setup. You can also buy an entire meter with probe for around $100 but no guarantee that it works.

I'd probably sell mine but of course it needs repair.

 

I’ll keep an eye out for one. Sometimes I luck out when a local shop is ready to dump their old gear. I just picked up two function generators for free. Nothing fantastic but useful for me.

 

I have been reading up on how to design your own dc clamp meter using a hall sensor. Goal being to build it tiny to slip between things. I wonder if it’s possible to get enough sensitivity to go down below the 3-4 mA I’ve seen on most.

 

I have been reading up on how to design your own dc clamp meter using a hall sensor. Goal being to build it tiny to slip between things. I wonder if it’s possible to get enough sensitivity to go down below the 3-4 mA I’ve seen on most.

The HP 428B has a 1 mA full scale range.

 

Are there ones that can measure down to uA?

 

I don't know of any. It's not easy, as you can't make a direct measurement but must work with the magnetic field. The earth's field needs to be accounted for. A direct current results in a steady magnetic field so one has to work with the 0.5 Gauss of the earth as a baseline.

Hall effect is one popular method but that has its difficulties.

The HP 428B is the most sensitive of which I am aware, at 1 mA full scale but again you need to zero out the static field for each measurement. I wish my 428A worked; it seems to have a problem with the probe. The $40 units from China aren't that sensitive I believe.

 

You can try a Tektronix CT-1 if you can find or make one.

Jim Williams application note in which he uses the current tranformer to measure the drive current to a quartz crystal:

https://www.google.com/url?sa=t&rct...williams.pdf&usg=AOvVaw3r4PNXfMC1rbInUQWC_hvS

It looks like a lot of work.

 

You can try a Tektronix CT-1 if you can find or make one.

Jim Williams application note in which he uses the current tranformer to measure the drive current to a quartz crystal:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=2ahUKEwjz06SdheHjAhWs7HMBHTEUDVQQFjABegQIABAC&url=https://static5.arrow.com/pdfs/2012/1/15/6/19/10/99/ltc_/auto/ltmag-v17n02-15-submicroampcurrentmeasurement-williams.pdf&usg=AOvVaw3r4PNXfMC1rbInUQWC_hvS

It looks like a lot of work.
View attachment 182961

It appears he is measuring ac not dc.

 

Yes, he is. I apologize for the distraction.