What are 6.5 Digit Multimeters Good For?
in [Design]
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From: Spehro Pefhany on 12 Mar 2010 07:23 On Thu, 11 Mar 2010 17:56:35 -0800, the renowned D from BC <myrealaddress(a)comic.com> wrote: >6.5 digit multimeters sell around $1000.00. >For electronics development, are these $1000 multimeters really >necessary? >What are they good for? If you're developing precise instruments, you would prefer to have test equipment that has higher (preferably MUCH higher) performance than the devices you are developing. Say you have designed a 0.1% or 0.01% current source for a sensor and want to confirm how much it drifts with temperature within 1%. It's not as easy when you approach or pass the limits of what has been done (or what you can afford to buy/rent/borrow) and you have figure out how the heck to test it. I don't see how a meter like that would be all that useful if you were only developing digital, audio or RF though. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff(a)interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
From: Jan Panteltje on 12 Mar 2010 07:30 On a sunny day (Thu, 11 Mar 2010 17:56:35 -0800) it happened D from BC <myrealaddress(a)comic.com> wrote in <MPG.26033f321480b139896e5(a)209.197.12.12>: >6.5 digit multimeters sell around $1000.00. >For electronics development, are these $1000 multimeters really >necessary? >What are they good for? They are not needed, all you need is a 5 Euro multimeter, and in extreme cases a precise reference. That means if you use one of those reference chips, you borrow the very accurate multimeter for a day, measure your reference chip, write it down, and use that to calibrate your cheap multimeter, or o compute it's real value, Saved: 1000$ Of course there are exceptions, but in places where that counts they usually have a lot of ++++expensive stuff anyways. Usually places where nothing really useful is done, like in CERN, or ITER, or LIGO, etc.
From: Uwe Hercksen on 12 Mar 2010 10:26 D from BC schrieb: > Of course there's always something better.. :P > 8.5 Digit multimeter Hello, if you carefully read the specifications of some 8.5 Digit multimeter, you will find out that you get the full performance only up to one day after calibration, at 20 +- 1 �C and only when measuring DC voltages between 1 and 10 V. ;-) Bye
From: Spehro Pefhany on 12 Mar 2010 11:09 On Fri, 12 Mar 2010 16:26:22 +0100, Uwe Hercksen <hercksen(a)mew.uni-erlangen.de> wrote: > > >D from BC schrieb: > >> Of course there's always something better.. :P >> 8.5 Digit multimeter > >Hello, > >if you carefully read the specifications of some 8.5 Digit multimeter, >you will find out that you get the full performance only up to one day >after calibration, at 20 +- 1 �C and only when measuring DC voltages >between 1 and 10 V. ;-) > >Bye Yeah, that's kind of a "maximum accuracy" spec (repeatability + short-term drift) You really have to read the specs on all multimeters. They can save a lot of money by "relaxing" the specs on other than the one or two primary DC voltage ranges. A meter with 0.1% accuracy on low DC voltages might be as bad as 1% for high currents, AC and high ohms, and sometimes even for high DC voltages.
From: Jim Yanik on 12 Mar 2010 11:29
Uwe Hercksen <hercksen(a)mew.uni-erlangen.de> wrote in news:7vv4ouF8r7U1(a)mid.dfncis.de: > > > D from BC schrieb: > >> Of course there's always something better.. :P >> 8.5 Digit multimeter > > Hello, > > if you carefully read the specifications of some 8.5 Digit multimeter, > you will find out that you get the full performance only up to one day > after calibration, at 20 +- 1 �C and only when measuring DC voltages > between 1 and 10 V. ;-) > > Bye > > one must always RTFM. (read the F-ing manual) -- Jim Yanik jyanik at localnet dot com |