EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: rccola777 on November 27, 2018, 03:58:00 pm
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I was recently watching a video from The Signal Path and he was using a Fluke 289 and while measuring a dc voltage it was also showing any ac ripple at the same time. This is something that would be very useful to me. Are there any meters that do this in a smaller form factor than the 289?
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I think the Brymen867s/869s are smaller and they do it, but they are certainly not small ;D
Not an uncommon feature if the meter has a dual display - the 121GW does it and is quite small for its performance/features.
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Keysight u1252b has the dual display too.
Can be set to display quite a few different parameters.
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I think the Brymen867s/869s are smaller and they do it, but they are certainly not small ;D
Not an uncommon feature if the meter has a dual display - the 121GW does it and is quite small for its performance/features.
121GW is showing only DC+AC on primary display , it could display both but they didn't do it .
For every meter you have to read carefully the specs , dual display is not a guaranty that it will show both DC and AC .
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I was recently watching a video from The Signal Path and he was using a Fluke 289 and while measuring a dc voltage it was also showing any ac ripple at the same time. This is something that would be very useful to me. Are there any meters that do this in a smaller form factor than the 289?
Of the meters I have looked at, the following support it.
Fluke 189
Fluke 97 scope meter
UNI-T UT181A (Fluke 289 clone)
TPI 194II (made by Summit)
Brymen BM869s
The Extech EX540 / CEM DD9939 with it's tri-display does not support it but it does have AC+DC. I am not sure about the Gossen Ultra. You would need to check.
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A bit strange that the most expensive handheld meter I have, the Gossen, doesn't support it.
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Brymen 525s can do it, both AC+DC and DC,AC
UNI-T UT195DS can sort of do it, it will show AC+DC on main display and toggle between DC and AC value on secondary display
Prova 903 is two meters and dual readout, using them in parallel with on on AC the other on DC would do the trick.
AC+DC is usual used about sqrt(sqr(VAC)+sqr(VDC))
Bench meters can also show DC,AC, but it will usual include a relay toggling inside the meter.
I used my review index and checked meters with dual displal, I skipped all them that is listed above.
https://lygte-info.dk/info/DMMReviews.html
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Hioki DT4282:
https://www.hioki.com/en/products/detail/?product_key=5570 (https://www.hioki.com/en/products/detail/?product_key=5570)
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The Brymen 867 also does both AC and DC at the same, it is basically a 869 without the temperature range.
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sorry for offtop
Is DSO a way to read AC+DC correctly?
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sorry for offtop
Is DSO a way to read AC+DC correctly?
Yes it is in principle, as long as it can provide Cycle RMS (for AC+DC RMS), Cycle Stdev (for AC RMS) and Mean (for DC) measurement functions.
Yet DSOs aren't meant to be precision instruments, and the majority of them is 8-bits only, hence the resolution is limited to some 0.5%.
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Yet DSOs aren't meant to be precision instruments, and the majority of them is 8-bits only, hence the resolution is limited to some 0.5%.
I think you might be off by an order of magnitude.
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Envoyé de mon iPad en utilisant Tapatalk
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Hioki DT4282:
https://www.hioki.com/en/products/detail/?product_key=5570 (https://www.hioki.com/en/products/detail/?product_key=5570)
Unfortunately, DT4282 millivolt range does not have dual display. And only the voltage AC+DC, no current AC+DC
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My Fluke 189 does it and it's great. Especially when you don't know if a voltage is AC or DC.
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Yet DSOs aren't meant to be precision instruments, and the majority of them is 8-bits only, hence the resolution is limited to some 0.5%.
I think you might be off by an order of magnitude.
Yeah, spec is typically 2-3% accuracy at best, maybe a 10 or 12 bit scope could be a bit better, but as mentioned, they're for showing precision time, not precision voltage.
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Yet DSOs aren't meant to be precision instruments, and the majority of them is 8-bits only, hence the resolution is limited to some 0.5%.
I think you might be off by an order of magnitude.
Yeah, spec is typically 2-3% accuracy at best, maybe a 10 or 12 bit scope could be a bit better, but as mentioned, they're for showing precision time, not precision voltage.
Mind you, resolution is something different than accuracy.
And 0.5% resolution means just +/-100 counts or 2 digits, which cannot compete even with the cheapest handheld DMM - that's what I was referring to. For 3-1/2 digits, we need 12 bits indeed.
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DMMs typically don't have much bandwidth. They do make some decent scopes with lower BW, higher resolution and better accuracy. I think that Hioki I showed is 0.1% accuracy for voltage which is still not all that great. I think it was using multiple 16-bit delta sigma convertors. Not suggesting it's a generic bit of equipment. Far from it. But a scope with some decent specs certainly could be designed if they are not available already.
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+1 for the Fluke 189
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Maybe Fluke will come out with their Classic Line . Fluke 189, 187, 87IV (all made in China. :-DD).
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I recently added a Yokogawa TY710 to the collection. It has simultaneous DC , AC display on the DC volts position, and the current positions.
(http://pdf.platan.ru/img_base/nn_hr/507171616.jpg)
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My Fluke 189 does it and it's great. Especially when you don't know if a voltage is AC or DC.
189 can't do well, it's V and mV is separate, and in dual mode it use the same range of AVC and DCV, this makes the area is different from that of ACV and DCV listed (e.g., measurement of dc power supply ripple) the resolution of the small voltage is not enough, such as measuring a 60 V power supply ripple, ACV and DCV will use 500 V range at the same time, listed clearly for dozens of millivolt ripple, 500 V range is too big
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Just a note on the Brymen though, when making simultaneous AC and DC measurements, the update rate slows considerably. So only suitable for steady measurements.
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keysight/agilent u1272a does the dual display AC, DC. It does the equivalent of RMS AC ripple - not peak to peak.
It does not auto range each one individually though - they would both be in the same range. So if you want more accurate ripple, setting it to a mV range for example the DC might be out of range and not display.
TRXBench youtube video where he shows it in action and compares it to an oscilloscope. RMS reading is quite close between the two.
https://youtu.be/OH6U2SKQaOw?t=2127