Reading Coils With a DMM

[sundownz Pro Seller]

I use a ~$300 DMM to measure our coils here at the shop... why ?

Well I'll show you...

* Our Dual-1 coil on a cheap meter.

* On our meter - factory spec is 0.84 ohms +/- 12%. This thing is dead on.

* Our Dual-2 on a cheap meter.

* On our meter - factory spec 1.85 +/- 12%. Again... 12% variance allows up to 2.07 and the meter only reads to the tenths place so it is dead on.

So. Keep that in mind when reading your coils on a cheaper meter.

Click to read more...

 

[Lakota 5,000+ posts]

Touch the leads and subtract the difference?

 

[sundownz Pro Seller]

Much of it is lead resistance - correct.

The cheap meters I've used also jump around alot measuring a coil - my meter is quite solid once it gets its reading. It will jump at most 0.1 back and forth. The little meter was jumping by 0.3 or so.

 

[tez4life Premium Member]

Dually noted,and quite interesting.

I need to purchase a good DMM.

 

[hrtbrk1 5,000+ posts]

cool

 

[James Bang 5,000+ posts]

as long as it's close enough, I don't care. close enough to know that the company labeled or shipped the correct VC config. $300, no thanks, i'd rather buy more speakers //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[bonesninja 5,000+ posts]

i use a $900 Fluke (of course i didn't pay hardly anything for it) its pretty much balls on. It also has a temperature sensor and can force a 4-20 milliamp signal (i do a lot of intrumentation loop tuning at work where you need to test unpowered instruments)

 

[MikeyB 5,000+ posts]

Neat. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[thevic24 5,000+ posts]

i use a pair of flukes i bought as a set($650) one is a true rms meter and the other is a clamp meter/amp probe that dose ac and dc amps. very, very accurite.

 

[bonesninja 5,000+ posts]

i use a pair of flukes i bought as a set($650) one is a true rms meter and the other is a clamp meter/amp probe that dose ac and dc amps. very, very accurite.

i bought a box of 40+ meters at an auction for $500. Most of them were fluke's and about half of them were still brand new...i found that $900 meter in the box also, so i kept that one and sold most of the others

 

[thevic24 5,000+ posts]

i bought a box of 40+ meters at an auction for $500. Most of them were fluke's and about half of them were still brand new...i found that $900 meter in the box also, so i kept that one and sold most of the others

what ya got left? iam looking for another dc amp probe...

 

[bonesninja 5,000+ posts]

what ya got left? iam looking for another dc amp probe...

just got a couple cheapo's left ... one's that can be bought for under $15 at a hardware store

 

[thevic24 5,000+ posts]

just got a couple cheapo's left ... one's that can be bought for under $15 at a hardware store

o well, my search will continue...

 

[Heide264 10+ year member]

We use flukes for any of our EE labs... I brought in my cheapo one I use for projects one time to compare them and it was pretty significant. I don't know if I'd spend the money on a fluke for projects as long as you keep in mind the properties of a cheapo one. Guess it depends on your use.

Calibration of anything I'd say either buy or maybe even see if you can rent a fluke. I know I bum one off the EE lab to configure my stuff when need be.

As far as just general measure and checks go normally my cheapo one is all I need.

Good thought to bring up on a forum like this =)

 

[mrogowski 5,000+ posts]

Error ratings are higher in all digital meters when low measuring values are concerned. You can increase the accuracy level of a meter simply by using a 100 Ohm precision resistor in series with your voice coil. A 50 cent fix for a more accurate reading //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Best,

Mark