What are 6.5 Digit Multimeters Good For?
in [Design]
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From: Jan Panteltje on 13 Mar 2010 08:21 On a sunny day (Fri, 12 Mar 2010 16:36:25 -0500) it happened Spehro Pefhany <speffSNIP(a)interlogDOTyou.knowwhat> wrote in <pnclp51o6nn5m3e7ip4o3ht7oecfnhu1sc(a)4ax.com>: >On Fri, 12 Mar 2010 12:43:08 -0800, D from BC ><myrealaddress(a)comic.com> wrote: > >>In article <hne7cu$st1$1(a)news.albasani.net>, pNaonStpealmtje(a)yahoo.com >>says... >>> >> >>> I have a controlled current souce. >>> Stuff 1 A through the .1 resistor and measure the voltage drop? >> >>Huh..My power supply does have constant I mode.. I'll try that someday. > >Be careful using power supplies that way. It's more intended as a >current limit than as a constant current supply. For one thing, it's >not very stable. A potentially bigger problem is the BFC across the >output, which means you might get a very high current for a while, >enough to destroy transistors etc. if the output cap is charged to a >high enough voltage. The current will eventually settle down to the >limit setting, but that could be small consolation if you've fried >something. Yes, better make something like this: + | load under test | 1A | + 1V ------------ + |/ out ------| NPN ----- - |\\ | opamp | | | -----------------------| | [ ] 1 Ohm | ///
From: Jan Panteltje on 13 Mar 2010 08:23 On a sunny day (Fri, 12 Mar 2010 15:31:33 -0600) it happened John Fields <jfields(a)austininstruments.com> wrote in <a3blp59kk10s93orbunu7mg8s921d1t56f(a)4ax.com>: >On Fri, 12 Mar 2010 20:33:42 GMT, Jan Panteltje ><pNaonStpealmtje(a)yahoo.com> wrote: > >>On a sunny day (Fri, 12 Mar 2010 10:50:48 -0600) it happened John Fields >><jfields(a)austininstruments.com> wrote in >><ekrkp5lg8obtcmftn2tmq8adsnlte9u59e(a)4ax.com>: >> >>>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 >> >>Sorry can you explain that again in electronics English? > >--- >If you can't understand it in plain English, what makes you think you'll >be any less confused in "electronics English", whatever that may be? > >The point I was making was that your statement that 6.5 digit >multimeters aren't needed is wrong, since without one you wouldn't be >able to determine the accuracy of the cheap multimeter. > > >JF I know a guy who was actually a technican, he started studying philoosphy. He showed mw one of his books. To make a long story short: Philosophy is not for me.
From: Jan Panteltje on 13 Mar 2010 08:25 On a sunny day (Fri, 12 Mar 2010 16:37:29 -0500) it happened Spehro Pefhany <speffSNIP(a)interlogDOTyou.knowwhat> wrote in <gvclp5hiif1sk4bti8qepfe7j4p5hjnk4l(a)4ax.com>: >On Fri, 12 Mar 2010 15:31:33 -0600, John Fields ><jfields(a)austininstruments.com> wrote: > >>On Fri, 12 Mar 2010 20:33:42 GMT, Jan Panteltje >><pNaonStpealmtje(a)yahoo.com> wrote: >> >>>On a sunny day (Fri, 12 Mar 2010 10:50:48 -0600) it happened John Fields >>><jfields(a)austininstruments.com> wrote in >>><ekrkp5lg8obtcmftn2tmq8adsnlte9u59e(a)4ax.com>: >>> >>>>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 >>> >>>Sorry can you explain that again in electronics English? >> >>--- >>If you can't understand it in plain English, what makes you think you'll >>be any less confused in "electronics English", whatever that may be? >> >>The point I was making was that your statement that 6.5 digit >>multimeters aren't needed is wrong, since without one you wouldn't be >>able to determine the accuracy of the cheap multimeter. >> >>JF > >By his logic, you wouldn't need a wife if your neigbor has one. You do not need a wife at all, you can have yourself cloned. Just imgine 2 of you having an argument ;-)
From: Jan Panteltje on 13 Mar 2010 08:27 On a sunny day (Fri, 12 Mar 2010 13:00:04 -0800) it happened D from BC <myrealaddress(a)comic.com> wrote in <MPG.26044b27299d843e9896f7(a)209.197.12.12>: >In article <hne8fg$uqm$1(a)news.albasani.net>, pNaonStpealmtje(a)yahoo.com >says... >> >> On a sunny day (Fri, 12 Mar 2010 10:50:48 -0600) it happened John Fields >> <jfields(a)austininstruments.com> wrote in >> <ekrkp5lg8obtcmftn2tmq8adsnlte9u59e(a)4ax.com>: >> >> >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 >> >> Sorry can you explain that again in electronics English? > >He means you still need an accurate tool to make use of a less accurate >tool. Which raises the question, why have the less accurate tool? > >btw... Boat anchor is a term I sometimes use for large heavy antiqued >test equipment. >Pre LCD scopes are boat anchors. Yes, OK, but Fields did not read very well, you only need the accurate one ONCE. And that means you can go to a place and have yor reference measured.
From: Jan Panteltje on 13 Mar 2010 08:30
On a sunny day (Fri, 12 Mar 2010 16:53:17 -0800) it happened D from BC <myrealaddress(a)comic.com> wrote in <MPG.260481d66c78414f9896fb(a)209.197.12.12>: >In article <Xns9D39C8D3FC146jyaniklocalnetcom(a)216.168.3.44>, >jyanik(a)abuse.gov says... >> >> D from BC <myrealaddress(a)comic.com> wrote in >> news:MPG.26044b27299d843e9896f7(a)209.197.12.12: >> >> >> > btw... Boat anchor is a term I sometimes use for large heavy antiqued >> > test equipment. >> >> >> >> > Pre LCD scopes are boat anchors. >> > >> > >> >> Not true. > >Yeah.. :P >CRT + linear transformer + steel chassis = boat anchor. >LCD + smps + plastic box = not boat anchor CRTs are cool, your own linear accellertor, cool physics. Few years from now they will become very valuable things. Also EM pulses do not kill CRTs. So after the next nuke war it is all you have to watch TV (if there is any): http://panteltje.com/panteltje/scope_tv/index.html |