RC India

RC Equipments => Servos, Gyros and All Electronics => Topic started by: MohitJindal on August 14, 2012, 07:41:08 AM

Title: Multimeter Burned my Circuit Board
Post by: MohitJindal on August 14, 2012, 07:41:08 AM
Hi; I have a UNI-T 830D multimeter. I connected it to a DC Servo motor circuit board. I checked the voltage; its perfect. But when I checked the current it burned my whole board :banghead:. No fire,no smell of burning but a brown color on the pins of a chip and the board is not working anymore. One thing I noticed;when I checked the current the values are fluctuating. How I can check actual correct current ? :help: Is buying only Ammeter a good option ? 8-). Fluke multimeter are best ? ???
Title: Re: Multimeter Burned my Circuit Board
Post by: SunLikeStar on August 14, 2012, 09:10:34 AM
I hope you know that current is measured in seriese and not parallel. I'm sure you know this already, just putting it down on the board.
Title: Re: Re: Multimeter Burned my Circuit Board
Post by: srivatsa on August 14, 2012, 10:18:09 AM
Adding to that.. Current mode = least resistance. there are good chance of shorting. Did you by pass any component?
Title: Re: Multimeter Burned my Circuit Board
Post by: MohitJindal on August 14, 2012, 03:32:41 PM
I know current is measured in series but how i make that series ? Also i didn't bypass any component.
On another day i checked current of a battery it burns my fingure.
Title: Re: Re: Re: Multimeter Burned my Circuit Board
Post by: srivatsa on August 14, 2012, 04:54:30 PM
You can't make the series unless you Break the circuit between.

Quote from: MohitJindal on August 14, 2012, 03:32:41 PMOn another day i checked current of a battery it burns my fingure.

current of a battery? i hope you know it doesn't mean anything unless something draws the current from it.. to measure current, the ammeter ( in your case, multimeter in current measuring mode) offers negligible resistance to the circuit. so its as good as short circuit. during which large current flows and the carrier heats up.
Title: Re: Multimeter Burned my Circuit Board
Post by: MohitJindal on August 14, 2012, 05:46:16 PM
Yes i attached the 2 wires coming out from battery to 2 wires of multimeter.
Main point is how i check current. Circuit board is running dc motor. I think desolder red motor wire and attach multimeter to it. Is that series ?
Title: Re: Multimeter Burned my Circuit Board
Post by: SunLikeStar on August 14, 2012, 06:50:42 PM
You are doing it all wrong. Request you to read some basics about current, voltage and multimeters.