Products > Test Equipment
AN8008 US $19, 9999count, 1uV, 0.01uA, 0.01Ohm, 1pF resolution meter
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mnementh:

--- Quote from: MacMeter on September 16, 2017, 07:23:06 pm ---
--- Quote from: Fungus on September 16, 2017, 07:02:20 pm ---
--- Quote from: MacMeter on September 16, 2017, 06:45:23 pm --- I've had problems in both hertz dial positions. So far I can't reliably reproduce the problems. In the first dial position for hertz and voltage, I get no readings for hertz at times, but can get a reading in the dedicated hertz dial position, then at times this behavior is just the opposite.

--- End quote ---

The AC mode "Hertz" function is probably only for low frequencies (mains AC).

The dedicated Hz function will probably go much higher.

If you don't get a reading, try swapping the leads around. These meters often need a zero crossing to work. eg. My AN860B+ only measures the frequency of Arduino pins when the leads are connected "backwards".

--- End quote ---

All my tests have been on 60 Hz sources, the Geny is a 3-phase crystal sync. However, come Monday I'll try your suggestion of reversing the leads. Thanks.

--- End quote ---

I'm thinking this may be the cause of your erratic readings. The meter may not be properly designed to count 3-phase AC; only single-phase.

As for those worrying about using it on mains... I could see if you were talking 440 or even 240VAC; but 120VAC? Hell... one of the old codgers (admittedly, a bit off in general, but still) I used to work with at the Ding & Dent Appliance store would use two fingers of one hand to test for presence of live AC when puttering around inside of microwaves and the like. 120VAC really still qualifies as "low-voltage" IMO; hell I've seen 12VDC powered amplifiers with +80V and -80V rails.


Cheers,


mnem
"Electrons may be very, very tiny; but when they gang up on you they always win." ~ me
MacMeter:

--- Quote ---I'm thinking this may be the cause of your erratic readings. The meter may not be properly designed to count 3-phase AC; only single-phase.

As for those worrying about using it on mains... I could see if you were talking 440 or even 240VAC; but 120VAC? Hell... one of the old codgers (admittedly, a bit off in general, but still) I used to work with at the Ding & Dent Appliance store would use two fingers of one hand to test for presence of live AC when puttering around inside of microwaves and the like. 120VAC really still qualifies as "low-voltage" IMO; hell I've seen 12VDC powered amplifiers with +80V and -80V rails.
Cheers, mnem
"Electrons may be very, very tiny; but when they gang up on you they always win." ~ me

--- End quote ---

I'm only reading a single phase at a time, voltage readings are accurate on each phase to neutral. It's the two "hertz" settings that act oddly, it could be the contacts in the meters "switch". I'll try to document the behavior in more detail this week, for those that like a good mystery.

And yes, I've heard the stories of the "old timers" using their fingers to detect voltage, never felt compelled to do it myself. Almost all of electrical readings I do are outside or in a studio, open air settings, temporary installations typical of most film and TV sets and locations. The few times I have to read a mains box in an electric closet or room, I would only probe with a "SAFE" meter. Most of the voltage we are exposed to is 120v. AC, and 220v AC measured between the generator phases. There are times when more power is needed in an underpowered studio, and the they rent one or two MegaWatt CAT generators that put out 480v AC, step down transformers are then used.
Mr. Scram:

--- Quote from: mnementh on September 17, 2017, 05:00:18 am ---I'm thinking this may be the cause of your erratic readings. The meter may not be properly designed to count 3-phase AC; only single-phase.

As for those worrying about using it on mains... I could see if you were talking 440 or even 240VAC; but 120VAC? Hell... one of the old codgers (admittedly, a bit off in general, but still) I used to work with at the Ding & Dent Appliance store would use two fingers of one hand to test for presence of live AC when puttering around inside of microwaves and the like. 120VAC really still qualifies as "low-voltage" IMO; hell I've seen 12VDC powered amplifiers with +80V and -80V rails.


Cheers,


mnem
"Electrons may be very, very tiny; but when they gang up on you they always win." ~ me

--- End quote ---
I know of plenty of smokers who could tar a ship with what went in their lungs each week and still died of old age, but I still wouldn't recommend it to anyone. MacMeter does seem to use it on 240V.

However, I'm not trying to be a safety nanny here. It's not criticism as such. I'm just interested in real life use I would consider a bit beyond the hardware. Even though I do things differently, it's an interesting opportunity to learn. I have been wondering whether anyone uses the AN8008 on mains on a regular basis and how that works out.
Fungus:

--- Quote from: Mr. Scram on September 17, 2017, 02:58:21 pm ---I know of plenty of smokers who could tar a ship with what went in their lungs each week and still died of old age, but I still wouldn't recommend it to anyone.

--- End quote ---

I'm sure there's plenty of people using DT830Bs on mains AC on a daily basis but I'd like to think that not many of them reside here.



--- Quote from: Mr. Scram on September 17, 2017, 02:58:21 pm ---I have been wondering whether anyone uses the AN8008 on mains on a regular basis and how that works out.

--- End quote ---

a) If it's always used correctly on the AC setting then probably nothing spectacular will happen. Safety features are for when you mess up, right?

b) If it simply dies a quiet death then "Crappy China" will be blamed, not the person who chose the meter.

mnementh:

--- Quote from: MacMeter on September 17, 2017, 11:44:32 am ---
--- Quote ---I'm thinking this may be the cause of your erratic readings. The meter may not be properly designed to count 3-phase AC; only single-phase.

As for those worrying about using it on mains... I could see if you were talking 440 or even 240VAC; but 120VAC? Hell... one of the old codgers (admittedly, a bit off in general, but still) I used to work with at the Ding & Dent Appliance store would use two fingers of one hand to test for presence of live AC when puttering around inside of microwaves and the like. 120VAC really still qualifies as "low-voltage" IMO; hell I've seen 12VDC powered amplifiers with +80V and -80V rails.
Cheers, mnem
"Electrons may be very, very tiny; but when they gang up on you they always win." ~ me

--- End quote ---

I'm only reading a single phase at a time, voltage readings are accurate on each phase to neutral. It's the two "hertz" settings that act oddly, it could be the contacts in the meters "switch". I'll try to document the behavior in more detail this week, for those that like a good mystery.

And yes, I've heard the stories of the "old timers" using their fingers to detect voltage, never felt compelled to do it myself. Almost all of electrical readings I do are outside or in a studio, open air settings, temporary installations typical of most film and TV sets and locations. The few times I have to read a mains box in an electric closet or room, I would only probe with a "SAFE" meter. Most of the voltage we are exposed to is 120v. AC, and 220v AC measured between the generator phases. There are times when more power is needed in an underpowered studio, and the they rent one or two MegaWatt CAT generators that put out 480v AC, step down transformers are then used.

--- End quote ---



Ummm... okay... so tell me, exactly how are you measuring individual phases with just a meter?

Last I knew, we still needed a 'scope for that. All 3 phases are still present on each leg; you can't ever get away from that. If your meter is made with a simple rectifier and notch filter designed for measuring single-phase AC, it's going to be totally out to lunch measuring 3-phase. This is one of the big differences between a Radidio Shack cheapie and a decent industrial meter; I suspect you may be falling into a similar trap here, especially after reading elsewhere about how all the clone meters are doing away with every last component they can get away with "...just to save 0.0001 per unit".

As for the old-timers doing stuff we'd consider daft; I never said I thought it was a good idea. But measuring an AC source you know to be 120V? I certainly wouldn't be afraid to use even the HFT "Little Red Box of Damifino" for that. Smeesh.

What's the best meter in the world? The one you have WHEN YOU NEED IT.


Good hunting,


mnem
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