hi,
under stress, teflon will move, ie 'cold flow'. if you were to use it, for example, as a wire wrap wire and you passed it such that it passed by, under tension, a wire wrap post, the teflon would most likely cold flow and allow the wire conductor to electrically connect to the wrap post. similarly, if a jumper wire is passed by the edge of a lead for example, and is under tension, the teflon insulation will cold flow and allow the conductor to short against the lead.
kynar insulation is much more resistant to cold flow.
phil
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Ken Patel
Sent: Tuesday, November 09, 2004 4:12 PM
To: [log in to unmask]
Subject: Re: [TN] Jumper Wire - Better insulation?
I never heard "cold-flow" word in my life (I am not EE!!??). Can someone
explain this to me?
Re,
Ken Patel
-----Original Message-----
From: COOKE, ROBERT W. (JSC-NX) (WGI) [mailto:[log in to unmask]]
Sent: Tuesday, November 09, 2004 8:31 AM
To: 'TechNet E-Mail Forum'; 'Ken Patel'
Subject: RE: [TN] Jumper Wire - Better insulation?
Ken,
For our applications, jumper wires are specified as solid, Teflon-insulated,
silver plated copper conductor (i.e.: wire wrap wire), although jumpers less
than 25mm (0.984 in.) may be uninsulated, provided the jumper is not liable
to short between lands or component leads, or cross over traces.
Type EE Teflon is rated at 1000V, +200C
Type E Teflon is rated at 600V, +200C
Type ET Teflon is rated at 250V, +200C
Standard kynar-insulated wirewrap wire, which has long been used as jumper
wire, is rated at 300V, +125C, and has good abrasion and cut-through
resistance. Tefzel is rated at 300V, +150C, and has good abrasion and
cut-through resistance, though cold-flow could be an issue.
If you have a design that routinely requires shorting / bridging links or
jumpers to hardwire-select options on the circuit board, there are zero-ohm
resistors available that are compatible with pick-and-place machines. They
are fairly expensive (compared to a regular resistor), but are required by
some customers that don't trust a piece of wire, and don't want to see any
thing on the board that looks "added".
Regards,
Bob
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ken Patel
Sent: Monday, November 08, 2004 5:44 PM
To: [log in to unmask]
Subject: [TN] Jumper Wire - Better insulation?
What different kind of jumper wire is available besides KYNAR as my boss is
looking for something thicker/better insulation than KYNAR?
Re,
Ken Patel
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