Here's an update to the message posted back on 15 Nov 96.


The equations for estimating current induced heating of flex 
circuits for currents up to about 1.5A are:

Current = ( 0.7101 dT + 33.283 ) x TA

dT = (1.408 Current / TA ) - 46.871

TA = Current / ( 0.7101 dT + 33.283 )

and for higher current levels:

Current = ( 10.477 dT^0.419 ) x TA^0.719

dT = ( ( Current / TA^0.719 ) / 10.477 )^2.386

TA = ( Current / ( 10.477 dT^0.419 ) )^1.391

Where:
Current = Current carrying capacity in Amps.
dT = Change in temperature in C.
TA = Cross section area of traces in sq.mm.


Rogers has computer software available that implements these 
equations, as well as conductor resistance calculations. It 
provides both numeric and graphic results, in English and Metric 
units.
     
     Andy Magee - Applications Engineer
     Rogers - Circuit Materials
     Tel: (602) 917-5237
     Fax: (602) 917-5256
     E-Mail: [log in to unmask]
     Website: http//www.rogers-corp.com/cmu
     
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