Re: Conductive Silver Ink Pen - Micro Tip - CW2200MTP
by maltesemanTS on Tue Mar 11, 2014 4:20 pm
CW2200 Alternate:Folks,
Consider the following conductive ink options:
CW2200 conductive pen (silver particles), with conductivity of .02-.05 ohm/sq/mil and an Adafruit price of $49.95 for 9g (.32 oz). A 10 in trace that is .1 inch wide and 1 mil thick (.001 inch) would be made up of 100 squares (0.1 inch x .1 inch in size). So the resistance would be 0.02-.05 ohm/sq/mil * 100 sq*mil =
2 to 5 ohms. Right :?:
CW2000 conductive pen (nickle filled polymer), with conductivity of 1.0-1.5 ohm/sq/mil and an Allied Electronics price of $11.80 for 9g (.32 oz). A 10 in trace that is .1 inch wide and 1 mil thick (.001 inch) would be made up of 100 squares (0.1 inch x .1 inch in size). So the resistance would be 1.0-1.5 ohm/sq/mil * 100 sq*mil =
100 to 150 ohms. Right :?:
CW2300 conductive pen (silver coated copper filled polymer), with conductivity of 0.07-.09 ohm/sq/mil and an Allied Electronics price of $33.60 for 9g (.32 oz). A 10 in trace that is .1 inch wide and 1 mil thick (.001 inch) would be made up of 100 squares (0.1 inch x .1 inch in size). So the resistance would be 0.07-.09 ohm/sq/mil * 100 sq*mil =
7 to 9 ohms. Right :?:
MG 8420-P conductive pen (acrylic based with silver), with conductivity of 0.2 ohm-mil and an Allied Electronics price of $29.95 for .3 oz.
This product vendor is different than for the other products. The MG 8420-P spec sheet lists actual resistivity in unit of ohm*mil, but this is equivalent to 0.2 ohm/sq/mil, which is surface (or sheet) resistivity:
(0.2 ohm-mil) * (1 mil think layer) / (1 mil x mil square area) = 0.2 ohm but commonly written as ohm/square to differentiate from bulk resistance. A 10 in trace that is .1 inch wide and 1 mil thick (.001 inch) would be made up of 100 squares (0.1 inch x .1 inch in size). So the resistance would be 0.2 ohm/sq/mil * 100 sq*mil =
20 ohms. Right :?:
Good luck making 1 mil thick traces; I'd guess they'll be quite a bit thicker!
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Now you have a choice depending on how much resistance you can tolerate for your project. CW2000 is significantly less conductive but significantly less expensive. Perhaps the CW2300 is the best compromise; again, it will be application specific depending on how much power you have at your disposal. It might be much more feasibly to simply bump up the power on your project to compensate for the higher resistivity and save a bunch of cash.--