| Products > Test Equipment |
| AN8008 US $19, 9999count, 1uV, 0.01uA, 0.01Ohm, 1pF resolution meter |
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| Fungus:
--- Quote from: Kalvin on August 30, 2017, 06:51:05 pm ---Quick test: My AN860B+ shows 1.553V, my two AN8008s show 1.555V and 1.554V. --- End quote --- So at 5V the AN8008s would average about 5 counts higher, just like mine. :popcorn: (do you have a voltage reference or a third meter to see which of the two is correct?) |
| Kalvin:
--- Quote from: Fungus on August 30, 2017, 06:58:18 pm --- --- Quote from: Kalvin on August 30, 2017, 06:51:05 pm ---Quick test: My AN860B+ shows 1.553V, my two AN8008s show 1.555V and 1.554V. --- End quote --- So at 5V the AN8008s would average about 5 counts higher, just like mine. :popcorn: (do you have a voltage reference or a fancy third meter to see which of the two is correct?) --- End quote --- Sorry, I do not have a fancy meter or voltage reference available. My best meter at the moment is UT-61E. Actually I did made a quick test previously against the UT-61E when I received the AN8008s: https://www.eevblog.com/forum/testgear/an8008-us-$19-10000count-1uv-0-01ua-0-01ohm-resolution-meter/msg1261915/#msg1261915 --- Quote ---Quick test: Took a 1.5V battery and measured the battery voltage with two AN8008 and one UT61E simultaneously: AN8008s displays 1.565 +/- 0.001 and UT61E 1.5655 +/- 0.0001. Current measurement test with the three DMMs in series in uA range: 3.37 uA +/- 0.01 uA. Modify message --- End quote --- All meters seem to agree pretty well. |
| Mark Hennessy:
--- Quote from: prof on August 30, 2017, 06:33:52 pm --- --- Quote from: Mark Hennessy on August 30, 2017, 06:27:12 pm --- --- Quote from: prof on August 30, 2017, 06:13:18 pm ---Although I'm using 2 rechargeable AAAs the diode tester has more Oomph than my Fluke. --- End quote --- The voltage for diode test is generated by a charge pump and regulator circuit, so is independent of the battery voltage. In a way, it's a shame they didn't make it fractionally higher - say, 3.3V - so people wouldn't assume they're seeing the battery voltage. --- End quote --- Doesn't matter how they do it. My point is it's better than the Fluke despite operating under worse conditions. ;) --- End quote --- Surely it's interesting to know what's happening? Anyway, my point is that there is a misconception that the diode test voltage is equal to the battery voltage. Even Dave says so in his review. It's an easy mistake to make, given that the chosen voltage is so very close that given by a pair of fresh alkaline AAAs, but it's a mistake nonetheless. Meanwhile, I've checked a handful of Fluke meters here, and the only one I've found that can't light a white LED is the Fluke 101. But the others run from 4 AAs or a PP3. Similarly, others have claimed that the square wave output comes from the charge pump supply, but that is also incorrect. Just trying to get accurate information out there :-+ |
| Mark Hennessy:
--- Quote from: Fungus on August 30, 2017, 06:58:18 pm --- --- Quote from: Kalvin on August 30, 2017, 06:51:05 pm ---Quick test: My AN860B+ shows 1.553V, my two AN8008s show 1.555V and 1.554V. --- End quote --- So at 5V the AN8008s would average about 5 counts higher, just like mine. :popcorn: (do you have a voltage reference or a third meter to see which of the two is correct?) --- End quote --- I've done a bit more checking, and the biggest error does seem to occur at 5V. I'm not sure why. Having said that, the AN860B+ is the least accurate of them all - the AN8002 and AN8008 all agree nicely with whatever Fluke I happen to compare them to. But still, we're talking about very small numbers of counts at worst - nothing to worry about IMHO. As you say, they are all meet their spec by quite some margin - how they do in a year or two is the really interesting question :-+ |
| MacMeter:
--- Quote from: Mark Hennessy on August 30, 2017, 07:32:53 pm --- --- Quote from: prof on August 30, 2017, 06:33:52 pm --- --- Quote from: Mark Hennessy on August 30, 2017, 06:27:12 pm --- --- Quote from: prof on August 30, 2017, 06:13:18 pm ---Although I'm using 2 rechargeable AAAs the diode tester has more Oomph than my Fluke. --- End quote --- The voltage for diode test is generated by a charge pump and regulator circuit, so is independent of the battery voltage. In a way, it's a shame they didn't make it fractionally higher - say, 3.3V - so people wouldn't assume they're seeing the battery voltage. --- End quote --- Doesn't matter how they do it. My point is it's better than the Fluke despite operating under worse conditions. ;) --- End quote --- Surely it's interesting to know what's happening? Anyway, my point is that there is a misconception that the diode test voltage is equal to the battery voltage. Even Dave says so in his review. It's an easy mistake to make, given that the chosen voltage is so very close that given by a pair of fresh alkaline AAAs, but it's a mistake nonetheless. Meanwhile, I've checked a handful of Fluke meters here, and the only one I've found that can't light a white LED is the Fluke 101. But the others run from 4 AAs or a PP3. Similarly, others have claimed that the square wave output comes from the charge pump supply, but that is also incorrect. Just trying to get accurate information out there :-+ --- End quote --- Agreed if you don't care "how they do it", you're on the wrong website! |
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