General > General Technical Chat
How do you calibrate your gear.
pickle9000:
Get a process calibrator.
807:
--- Quote from: chinoy on November 03, 2023, 11:22:47 am ---...I need to turn a trim pot till I get 0.45 volts
If every meter is giving me a different reading Im not sure which one to trust...
...I have some other 6000 count no name meters but even here every reading is different...
--- End quote ---
As other members have mentioned, it's normal for different meters to give different readings. The point is, how different are these readings? Give us some actual measurements. Just saying that they are different has no significance. If you set the pot to give 0.45v on one meter, what readings do you get on the others?
rdl:
You might not want to spend the money but there are cheap voltage references available on eBay and probably on AliExpress.
bdunham7:
To sort of answer the OP's question with an example, I set up the following small bench experiment:
I set up an AWG (SDG2042X) to put out 450mVRMS @ 5kHz plus the 15th harmonic @ 900mVp-p and combined that with 50mV of noise with a 20MHz BW. Oddly the channel combine feature didn't work as I expected, but that's a different issue--it displayed on a scope as you'd expect but an an amplitude different than I get adding them all up.
I then measured that signal with every DMM within reach and with the scope (SDS2354X-E) as well, using the StdDev function. Here they are rounded to 100µV for consistency and suppression of irrelevant digits. No surprises IMO. On meters with separate mVAC and VAC ranges, I tested both as they did vary on some models.
Siglent SDS2354X-E: 310.5mV
Fluke 8506A, Hi-Accuracy mode: 310.6mV
HP 34401A: 307.6mV
Fluke 8808A: 307.5mV
Fluke 8842A: 307.1mV
Fluke 289: 307.0 (both mVAC and VAC)
Fluke 189: 297.2mV (mVAC), 0.3042V (VAC)
Fluke 116: ~300mV (mVAC, very unstable), 0.225V (VAC)
Fairchild 7000A (AVG responding): 0.2832V
Fluke 27 (AVG responding): 280.0mV (mVAC), 0.282V (VAC)
and (I almost forgot it) my old friend the Fluke 98 Scopemeter, after some careful setup....310.4mV (multimeter mode, 100µs/div, 300mV range) w/ ~ 1.0mV peak noise. It also displayed a reasonably stable 0.310V in the 1V range at the same timebase setting.
CJay:
Man who has one watch knows the time, man who has two watches is never sure.
Seriously though, the big question is does it need to be absolute accuracy or just repeatably inaccurate?
I.E. if it indicates 0.45V when it's actually 0.47V or 0.43V does it make a damn of difference as long as the error is always the same?
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version