What are 6.5 Digit Multimeters Good For?
in [Design]
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From: John Fields on 12 Mar 2010 11:50 On Fri, 12 Mar 2010 12:30:31 GMT, Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote: >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 $1000 multimeters really >>necessary? >>What are they good for? > >They are not needed, all you need is a 5 Euro multimeter, >and in extreme cases a precise reference. >That means if you use one of those reference chips, you borrow >the very accurate multimeter for a day, measure your reference chip, >write it down, and use that to calibrate your cheap multimeter, >or o compute it's real value, >Saved: 1000$ --- If you don't _need_ the accurate multimeter, then how do you get around the fact that unless you use _it_ to measure the reference, your cheap multimeter is pretty much a boat anchor? JF
From: Fred Bartoli on 12 Mar 2010 11:56 Jan Panteltje a �crit : > 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 $1000 multimeters really >> necessary? Depends on what you're doing (just got a 8.5 digits 3458A) >> What are they good for? > Calibrate my 6.5 and 7.5 digits DMM? And few other things too... > They are not needed, all you need is a 5 Euro multimeter, > and in extreme cases a precise reference. > That means if you use one of those reference chips, you borrow > the very accurate multimeter for a day, measure your reference chip, > write it down, and use that to calibrate your cheap multimeter, > or o compute it's real value, > Saved: 1000$ > > 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. > Trying to imply that since you have nothing more than a $5 DMM you're doing useful things? Then trash all your tools and you'll get really important... -- Thanks, Fred.
From: John Larkin on 12 Mar 2010 12:19 On Fri, 12 Mar 2010 12:30:31 GMT, Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote: >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. Does your e5 multimeter resolve microvolts? If not, it's useless for designing thermocouple stuff. Can it measure resistance to 0.02%? That is useful too. If all you do is muck around with uPs that have 8 bit ADCs, a cheap meter is almost good enough. One cool thing to do with a good DVM is measure voltage drops in PCB traces and planes, often microvolts. That answers the eternal question. "where is the damned current going?" John
From: D from BC on 12 Mar 2010 12:19 Neato :)
From: D from BC on 12 Mar 2010 12:21
In article <ghfjp5d9k4u3nr23r4miuu3b85lshl4a7q(a)4ax.com>, speffSNIP(a)interlogDOTyou.knowwhat says... > > 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 Thanks :) |