"Free Harbor Freight DMM"

[Jack Crow]

Hi all,
Been lite on useful projects of late.
This is one I had wanted to do for a long time.

Make a meter holder for 'free' Harbor Freight meter.
Strictly for fun.

I used the HP 3456A as the background.

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Like I said, just for fun.

Jack Crow aka Radio Mike

[Mooselake]

They keep stuffing those in the bag on my rare HF (closest is 200 miles away ) trips, must have 3 or 4 of them. A while back I breadboarded a meter calibrator with a sample precision reference chip and tested all my DMMs. The HF was within a few hundredths of a volt at 5.000, good enough for Moose work

Kirk

[Jack Crow]

Kirk
They are not bad, just cheesy.
They have no mass, and tend to slide around on the bench.
The bracket will keep that from happening.
Snicked into the bracket, it is in there firmly.
If you want the STL's, let me know, happy to share with the team here.
There is a cup, pivot, and lower. The steel part is right out of the hardware store.

As you can tell, Im something of a DMM snob.
The HF meter, is the instrument we love to hate I suppose.

There are guys on the web modifying these things for LED back lights. Kinda cool.

The HP3456A is old.
That is why I got it for cheap.
It has not been to a lab in years.
Yet it's more than good enough for anything I am likely to do.
Systems DVM's are a bit different that what most people have on their benches.

Would be cool to make the hook up's and get the IEEE488 buss working.
Let's say you wanted to see just how stable a power supply was over a span of hours.
Such a set up can draw you a graph, min, max and other statistical measurements.
It can flip from accurate DC to very accurate True RMS AC measurements up to 1Mhz (most meters are rated at only power line frequency)
That info can be measured and extracted, depending on the program used.

Imagine making 100k measurements and using the computers power to give you an average.

I was calibrating them at the other end of the career when they were new.
For most things it is almost useless and cause people to go astray.
New users get what I call 'zero madness', like trying to make the thing display 15.0000 from a power supply that can't be adjusted that fine.
Most power supply's are not dc standards like a Fluke 335A or Fluke 5101.

It's fun, and good for male ego. Face it, male ego is very important when trying to impress others.

Or to steal a line from the former president of the galaxy...
Zaphod Beeblebrox once said.
“If there's anything more important than my ego around, I want it caught and shot now.”
or...
“If I ever meet myself,' said Zaphod, 'I'll hit myself so hard I won't know what's hit me."

Hope all is well in your part of the world.
WX here is up and down the dial. The day started in the 60's and I just froze walking the dogs tonight.

Keep it sane
Jack Crow aka radio Mike

[Mooselake]

[lairdb]

Incidentally, I had a similar dimestore DMM that kept annoying me, and made a probe holder for it -- much happier.





Don't have it handy to take a real picture of, but FWIW.

[Jack Crow]

L
That is a good idea.
May make use of it.
Many thanks
Jack Crow