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Discussion Starter #1
I just bought a new multi-range digital-multimeter to help with some electrical problems i've been having. I bought a book from sears for $10 that pretty much gives you an electrical engineering degree after your done... Anyway i still don't know if i'm using the meter correctly. I know how to check for voltage and stuff like that but i'm not sure if i am checking the resistance correctly. When i check for ohms (the up side down funky "U") the meter flashes numbers sporadically. The number that it flashes first is usually the specified resistance for the circuit i'm testing, but then it starts flashing numbers like crazy until it goes down to zero. Is this what is supposed to happen? Thanks for the input!
 

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sounds like the circuit you're trying to check resistance also has a capacitor on it somewhere...
capacitors store energy and will cause funky readings like that.

what exactly are you trying to test?

(and yes, I'm an electrical engineer myself, so I've seen it before. :) )
 

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Discussion Starter #3
Matt93SE said:
sounds like the circuit you're trying to check resistance also has a capacitor on it somewhere...
capacitors store energy and will cause funky readings like that.

what exactly are you trying to test?

(and yes, I'm an electrical engineer myself, so I've seen it before. :) )
coils on my 300zx.
 

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ahh, yes.. they have a capacitor inside them, so they're not going to read a constant resistance.
it should be around 0.7 ohms, but with a resistance that small, there's bound to be a bit of wandering in it, as well as the capacitors in there causing the resistance to slowly creep up/down anyway.
 

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Discussion Starter #5
Matt93SE said:
ahh, yes.. they have a capacitor inside them, so they're not going to read a constant resistance.
it should be around 0.7 ohms, but with a resistance that small, there's bound to be a bit of wandering in it, as well as the capacitors in there causing the resistance to slowly creep up/down anyway.
Okay. Yeah. Because when I first touch the test leads on the circuit it reads about 0.7 ohms and then starts jumping around. So I just figured whatever it said first is the right reading... Is that correct?
 

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Coils are going to be hard to test with a muliti-meter. Unless you get the really good grade of meter it wont put out enough volatage to acurately test resistance especially on a coil. I don't have a z car so I am not real familiar with them, but my bmw coils I can switch from one cylinder to another to find the bad one by process of elimination. My Nissan has a distributor and single coil. If I was looking for spark I'd start at the plugs and go backwards because the further I go the more expensive it gets.
 

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I thought I'd make a note that since your ohming things And I'm assuming it's your first multi-meter. Whenever you ohm something make sure there is no current in the circuit. Just a note, not sure if you knew.
 

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Yep, good advice, I roasted a Brand new Fluke Meter that way... 400 bucks gone in an instant... :) then I took an electronics engineering course :)
 

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Discussion Starter #9
ittamaticstatic said:
I thought I'd make a note that since your ohming things And I'm assuming it's your first multi-meter. Whenever you ohm something make sure there is no current in the circuit. Just a note, not sure if you knew.
Oh yeah. I made sure to read the manual twice before i started using it...
 

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Some lessons are learned the hard way for suure. Another note is when using your meter like the flukes that have a 9v battery be careful that what ever electronic device you are checking in series can handle 9volts. If not then say bye bye to what ever it is you fried.
 

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Discussion Starter #11
ittamaticstatic said:
Some lessons are learned the hard way for suure. Another note is when using your meter like the flukes that have a 9v battery be careful that what ever electronic device you are checking in series can handle 9volts. If not then say bye bye to what ever it is you fried.
I just have a cheap craftsman one... I think it uses 2 aa's or something. but thanks for the advice. I'll try and remember that.
 
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