ESD Mat - Page 1
Forum section: electronics / beginners

author: stafil
author_rank: Regular Contributor
timestamp: April 19, 2020, 09:35:33 pm
content: Can someone recommend an ESD May that is dissipative on the front side and conductive on the back? Like the one mentioned by Dave here:https://youtu.be/7FFrZl9ymFwI tried a couple from Amazon and DigiKey and both of them seem to be dissipative on both sides(my multimeter can’t measure the resistance no matter how close the probes are)These are the ones I tried:https://www.amazon.com/gp/product/B07PDT6JVMandhttps://www.digikey.com/product-detail/en/desco/45010/16-1234-ND/299817Also, any idea how to connect this:https://www.newark.com/pomona/5531/static-protection-wrist-band/dp/02B1554to this:https://www.digikey.com/product-detail/en/desco/09838/16-1158-ND/3043259Sorry I don't know the exact terminology. I think it's "ring connector" to "female banana"?

author: Bhutt
author_rank: Contributor
timestamp: April 19, 2020, 10:15:42 pm
content: https://www.digikey.ca/product-detail/en/scs/770096/SCP765-ND/9478147I got this one in because it was rubber, seen that recommendation on a EEVblog video. But same thing, first thing I did was test it with a MM but nothing. Maybe they don't work that way?It seems good quality though.Cheers

author: MarkF
author_rank: Super Contributor
timestamp: April 19, 2020, 11:54:07 pm
content: I bought this one:FT Series 2-Layer Rubber Worktop Mat Kit with Wrist Strap, Ground Cord and Two Snaps, Dark Blue/Black, 24 x 48 x .080

author: MarkF
author_rank: Super Contributor
timestamp: April 20, 2020, 12:00:19 am
content: Quote from: stafil on April 19, 2020, 09:35:33 pmYou can cut the wire lug off and put the wire in the plug.Or, screw the wire lug under the face plate screw of the receptacle and not use the plug.

author: jpb
author_rank: Super Contributor
timestamp: April 20, 2020, 09:56:15 am
content: Quote from: Bhutt on April 19, 2020, 10:15:42 pmA MM won't be able to measure it. I use an insulation tester (Fluke 1507 which applies a 1000V and can measure Gohms which is what you need.)

author: Whales
author_rank: Super Contributor
timestamp: April 20, 2020, 10:11:54 am
content: If it's Gohms then doesn't that defeat the point?

author: jpb
author_rank: Super Contributor
timestamp: April 20, 2020, 11:31:08 am
content: If you just measure the underlying conductive layer, yes you can measure it with a normal DMM.But if you want to test the upper dissipative layer then it will be much higher resistance. For example, just sticking two probes onto my mat gives a resistance of about 5Gohms. If I stick probes on the underside then it is a few kohms.The resistance on the surface needs to be high because though the charges are at a very high voltage they are small and you want them to dissipate reasonably slowly so as to not cause damage but the small charge will dissipate even with a very low current.Some mats are more conductive than others e.g. this one:http://documents.staticcontrol.com/PDF/R3-Rubber-Worksurface-Mat.pdfstates resistance in the range 10^6 to 10^9 but even so, a normal DMM such as a Fluke 87V only measures up to 50Mohms so will have trouble if the particular sample is nearer to 1Gohm rather than 1Mohm.A high resistance also allows normal electronics to be placed on it without risking a short-circuit while still dissipating any ESD.

author: Whales
author_rank: Super Contributor
timestamp: April 20, 2020, 11:37:09 am
content: I was thinking of the conductive side. Bhutt's post suggested he couldn't measure anything at all.

author: stafil
author_rank: Regular Contributor
timestamp: April 20, 2020, 05:40:54 pm
content: Quote from: Whales on April 20, 2020, 11:37:09 amCorrect. I was measuring the “conductive” side.