Quote:
Originally Posted by Radio Wrangler
DVMs are a bit easier, and as Jeremy says they deliver what they promise and they prove very reliable and very stable. This is good, isn't it? because most people trust them.
I have a trio of high resolution DVMs. They are long out of cal, but they agree amongst themselves. They have NOT been adjusted to do so, so I trust them to not be very far from where they were when they were used in their respective cal labs.
If I wanted to make a calibrated measurement, I would use a calibrated meter and the afterwards I would send the calibrated meter off for cal. Provably calibrated measurements are only those made in the period between two calibration passes.
This is probably overkill for checking an avometer movement, I suspect.
David
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Earlier in the thread I'd mentioned an 80s bench Fluke I have was reading spot on what an good Agilent was reading and it's never been adjusted at all. I've got a few Flukes which are like this.
I've been using an Agilent at work (different Agilent to the previously mentioned) which has more drift than a snow storm, so putting that against something else can cause confusion.
How 'overkill' something is depends on how certain you want to be, or how accessible you want for a nationally traceable standard to be.
If you want to set an Avometer movement to FSD, then how overkill is overkill to know that it's reading correctly at FSD? If I adjust the shunt on a model 7, shouldn't I know it's where it should be? How overkill is knowing that it's right?
It all comes down to what one wants, how serious someone is about a task, if it's a hobby then it comes down to how serious someone wants to take the hobby, whether or not they're in the electrical/electronics field for employment.
Even if someone takes a good meter to a cal lab and just pays for a 'report of readings' or something to that effect, rather than spending on cal each year. That could be an idea, but apart from testing at intervals I'm not sure what the cal lab would see the difference to be.