Electrically conductive-resistive carbon fiber thread needed
Electrically conductive-resistive carbon fiber thread needed
(OP)
I'm looking for a small diameter carbon fiber thread supplier or source that makes and sells a "sewing?" thread that is electrically conductive with considerable resistance. I've ordered a 1 lb spool of "carbon fiber graphite yarn tow" from Aircraft spruce and Specialties- this is typically used for winding and fabricating various carbon fiber structures/reinforcements and it measures about 12 Ohms per ft. I'm looking for something much smaller and thus with much higher electrical resistance, approx 500k Ohms per ft.
Ideally the "thread" material will be flexible and multi-stranded for reliability during flexing and build operations. I anticipate needing to coat or protect the carbon "conductors" using a dipped/sprayed conformal coating or polymer sheath- but maybe somebody already makes a small diameter "high resistance" wire? Spark plug wires are similar today- but the insulation diameter is huge and the spark plug wire is not always continuous to DC voltage but relies on "spark gap jumps" to work properly.
My application involves using the wires in RF fields where high DC resistance appears "invisible" and does not perturb the various RF fields. Definitely very low voltages and currents only. I've seen a bit of mention online about MRI catheter wires using carbon but no supplier, etc.. I'd like to find a cheap, high volume material/source for this application. Seems like I've seen what looked like tiny carbon/cotton/polyester "wires" used for microphones, telephones, and USB in the past- but I simply cannot find any current (domestic USA) suppliers after considerable searching. Any ideas out there?
I'd also consider a small 2D or "flat" carbon or vacuum deposited conductive tape if it is available and has similar properties.
Thanks in advance for your suggestions and comments!
Ideally the "thread" material will be flexible and multi-stranded for reliability during flexing and build operations. I anticipate needing to coat or protect the carbon "conductors" using a dipped/sprayed conformal coating or polymer sheath- but maybe somebody already makes a small diameter "high resistance" wire? Spark plug wires are similar today- but the insulation diameter is huge and the spark plug wire is not always continuous to DC voltage but relies on "spark gap jumps" to work properly.
My application involves using the wires in RF fields where high DC resistance appears "invisible" and does not perturb the various RF fields. Definitely very low voltages and currents only. I've seen a bit of mention online about MRI catheter wires using carbon but no supplier, etc.. I'd like to find a cheap, high volume material/source for this application. Seems like I've seen what looked like tiny carbon/cotton/polyester "wires" used for microphones, telephones, and USB in the past- but I simply cannot find any current (domestic USA) suppliers after considerable searching. Any ideas out there?
I'd also consider a small 2D or "flat" carbon or vacuum deposited conductive tape if it is available and has similar properties.
Thanks in advance for your suggestions and comments!





RE: Electrically conductive-resistive carbon fiber thread needed
http://ww
http://www.no-contact.com/
Info on Aracon
http://
http://www.glenair.com/composite/pdf/I-01.pdf
Chris DeArmitt
RE: Electrically conductive-resistive carbon fiber thread needed
http://www.fibraplex.com
But the resistance that you seek is very high. If you took one filament of carbon out of your 12,000 filament tow it would have about the right amount. That is 7 micron diameter and is virtually invisible.
By the way, if a single filament of carbon fiber gets into the composite used to make a composite aircraft radome, it can cause the whole dome to fail. The radar energy will vaporize the filament and the heat chars the resin, which then becomes conductive enough to continue charring.
RE: Electrically conductive-resistive carbon fiber thread needed
Thanks Again, "Maniachalengineer"
RE: Electrically conductive-resistive carbon fiber thread needed
Long skinny lengths would be make a very resistive line and high overall impedance. i.e. 5 foot (60") x 0.1" would measure 25 ohm per square x 60/0.1 = 15,000 ohms. Attach it to monofilament fishing line for support.
The polarization of your RF field would affect your actual wave impedance.
Can you say how you plan to use it?
kch
PS: the resist material is a challenge to get at since there are protective layers on both sides of the resist. You can couple to it capacitively more easily.