Author Topic: You need at least 4 multimeters?  (Read 9035 times)

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Offline miceuz

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You need at least 4 multimeters?
« on: March 04, 2014, 06:54:19 pm »
Does anyone remember in which episode Dave talks that you need at least 4 multimeters? One my friend just got caught by burden voltage trap, I want to give him some additional food for thought  ;D

Offline hans

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Re: You need at least 4 multimeters?
« Reply #1 on: March 04, 2014, 08:12:33 pm »
Episode 110, let's design a SMPS @ 31:20

It was about the efficiency Dc/Dc converter, so you need input voltage/current and output voltage/current
 

Offline uwezi

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Re: You need at least 4 multimeters?
« Reply #2 on: March 04, 2014, 11:08:34 pm »
Episode 110, let's design a SMPS @ 31:20

It was about the efficiency Dc/Dc converter, so you need input voltage/current and output voltage/current

And then you need a fifth one when you want to measure something which is inside the circuit, while still monitoring input and output. In other words, you cannot have too many multimeters - because then there is always number six, which is currently without battery...
 

Offline dr_p

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Re: You need at least 4 multimeters?
« Reply #3 on: March 04, 2014, 11:17:35 pm »
And you have to like all of them, so you need at least 10 to choose the 6 from.
 

Offline zapta

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Re: Re: You need at least 4 multimeters?
« Reply #4 on: March 05, 2014, 02:32:54 am »
And you have to like all of them, so you need at least 10 to choose the 6 from.

And then there are the cases when you work on two DC/DC at the same time...

I am getting alone with one.

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Offline Pillager

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Re: You need at least 4 multimeters?
« Reply #5 on: March 05, 2014, 04:38:00 am »
... In other words, you cannot have too many multimeters ...

Yes, you can. Fluke has so many they're selling them... ;D
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Offline Fsck

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Re: You need at least 4 multimeters?
« Reply #6 on: March 05, 2014, 05:02:57 am »
And you have to like all of them, so you need at least 10 to choose the 6 from.

occasionally, you might actually need/want all 10.
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Offline Jon86

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Re: You need at least 4 multimeters?
« Reply #7 on: March 05, 2014, 05:38:48 am »
And you have to like all of them, so you need at least 10 to choose the 6 from.

occasionally, you might actually need/want all 10.

In what situation?
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Offline robrenz

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Re: You need at least 4 multimeters?
« Reply #8 on: March 05, 2014, 05:42:43 am »
For a post picture in show your multimeters  :-DD

Offline Dave Turner

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Re: You need at least 4 multimeters?
« Reply #9 on: March 05, 2014, 06:34:54 am »
Don't forget the obligatory analogue meter(s).

I wouldn't be without my TMK 500, which is at least 30 years old, replacing another old trusty from the 60s (unfortunately accidentally destroyed by a friend  |O). Yes it has a 'burden' of 30k ohm/VDC, and requires careful thought before choosing the range and interpreting results.

Nevertheless analogue meters still have their place as discussed in another thread.
 

Offline Fsck

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Re: You need at least 4 multimeters?
« Reply #10 on: March 05, 2014, 07:24:07 am »
And you have to like all of them, so you need at least 10 to choose the 6 from.

occasionally, you might actually need/want all 10.

In what situation?

some kind of electronic function test.
something with many sensors.
troubleshooting/analyzing a multiple channel power supply
there's a bunch of RF applications
characterizing a whole system for repeatability

the 3458a feels like the defacto physics research bench DMM. to save money, many labs combine it with a switch system to have multichannel capabilities. which gives you similar capabilities to multiple DMMs: I've seen this more often in SS&CM physics. on the other hand, I've also seen some labs equipped with half racks of 3458's and a high speed switch system for faster acquisition and higher accuracy or to ensure certain sets of measurements are done simultaneously: more common for particle physics.

addendum: need for 4 -> it's pretty common to want 2 voltage readings and 2 current readings simultaneously.
« Last Edit: March 05, 2014, 07:25:43 am by Fsck »
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Offline madshaman

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You need at least 4 multimeters?
« Reply #11 on: March 05, 2014, 07:41:13 am »
I don't understand how anyone can get by with just four DMMs :-)
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Offline robrenz

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Re: You need at least 4 multimeters?
« Reply #12 on: March 05, 2014, 07:49:51 am »
At least 2 of the 4 must have built in graphing :-+

Offline gdewitte

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Re: You need at least 4 multimeters?
« Reply #13 on: March 05, 2014, 08:05:03 am »
You really need an odd number, so they can vote…
 

Offline sacherjj

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Re: You need at least 4 multimeters?
« Reply #14 on: March 05, 2014, 08:10:31 am »
You really need an odd number, so they can vote…

If you have an even number voting, you can cast the last vote towards what direction you "need" the measurement to go. 
 

Offline Jon86

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Re: You need at least 4 multimeters?
« Reply #15 on: March 05, 2014, 09:52:26 am »
I wonder how big the largest collection of multimeters on here is...
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Offline pickle9000

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Re: You need at least 4 multimeters?
« Reply #16 on: March 05, 2014, 09:56:47 am »
I wonder how big the largest collection of multimeters on here is...

Ask Dave.
 

Offline Astroplio

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Re: You need at least 4 multimeters?
« Reply #17 on: March 05, 2014, 10:29:12 am »
You really need an odd number, so they can vote…

If you have an even number voting, you can cast the last vote towards what direction you "need" the measurement to go.

LOL you guys!
 
 

Offline babysitter

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Re: You need at least 4 multimeters?
« Reply #18 on: March 06, 2014, 07:24:38 am »
I would say you need two DMM (for both labs), Computer control (GPIB) and a Multiplexer O0
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Offline GiskardReventlov

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Re: You need at least 4 multimeters?
« Reply #19 on: March 06, 2014, 08:38:56 am »
What's the handheld:bench ratio though?
 

Offline Dave

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Re: You need at least 4 multimeters?
« Reply #20 on: March 06, 2014, 01:12:50 pm »
What's the handheld:bench ratio though?
4:7
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Offline BMac

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Re: You need at least 4 multimeters?
« Reply #21 on: March 07, 2014, 12:04:47 am »
Really, can you ever have enough test equipment, ooohh wait i see a new shiny piece of test equipment, gotta go!

BMac
 

Offline rjk5378

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Re: You need at least 4 multimeters?
« Reply #22 on: March 07, 2014, 02:08:24 am »
You also need experts on this forum and elsewher to opine often about the need for multiple multimeters and other types of equipment. This is useful when one needs to convince the bean counters at work or, as in my case, for the hobbiest to justify yet another expenditure to the spouse! And, in that regard, having lots of test gear on the bench makes it less obvious that I have smuggled in a new addition. I see each and every unit in all its beauty, but my wife just sees a bunch of junk! <g>
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Offline GiskardReventlov

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Re: You need at least 4 multimeters?
« Reply #23 on: March 07, 2014, 10:15:12 am »
having lots of test gear on the bench makes it less obvious that I have smuggled in a new addition. I see each and every unit in all its beauty, but my wife just sees a bunch of junk!

So true.  A variation on this theme is to maintain a certain level of messiness, it's easy to camouflage something new.  Don't leave the shipping carton laying around though.
 

Offline BravoV

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Re: You need at least 4 multimeters?
« Reply #24 on: March 07, 2014, 02:57:36 pm »
Once you have graduated and have enough in the progress of collecting more and more DMMs  >:D, then don't forget the task on getting more ... <gulp> ... bench power supplies !!!  :-DD

Damn .. the curse never ends.  :palm:


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