PWB TRACE RESISTANCE CALCULATOR FOR RECTANGULAR CROSS-SECTION 

Trace Resistance

Inputs

Trace Width
W
Trace Length
L
Trace Thickness
T
Temperature
Temp....Set to 20 Degrees C for zero Temperature coefficient effect (TCR)

Output

Resistance (R): 
 
 
 THIS CALCULATOR WAS MODIFIED FROM 
EEWEB 
http://www.eeweb.com/toolbox/trace-resistance
USING IPC VALUES FOR PWB COPPER FOIL
AND TO SET THE ZERO BIAS POINT TO 20 DEG. C

International Annealed Copper Standard (IACS) for 100 percent conductivity per  IPC SPECIFICATION IPC-TM-650.


NOTE: FOR TRAPEZOIDAL CROSS SECTION WHICH IS TYPICAL OF ETCHED CONDUCTORS IS DISPLAYED
IN THE FIGURE BELOW ....JUST ENTER "NEW W" AS:

"NEW W" = 0.5 * (W2+W1)  

FOR EXAMPLE:
W2 =10 MILS W1=12 MILS
"NEW W"  TO ENTER IN ABOVE APPLET...
'NEW W" = 0.5 *(10+12)=11

NOTE : THE THICKNESS CAN BE SPECIFIED 
​IN DIMENSIONS OR IN OZ-CU (IE " 0.5, 1"
EDITED REV2 1-17-2022

Introduction

The purpose of this calculator is to solve for the resistance of a PWB copper conductor based upon physical dimensions and the copper foil volume resistivity. The resistance of a trace can be useful in many ways. The power dissipation in a trace is calculated after determining the trace resistance. The trace resistance can also be helpful if a circuit requires precision resistors and the pcb traces can effect the resistance value.

The equation for resistance of a rectangular conductor cross section is shown in the header of this web page where

ρ=Volume Resistivity (Ω-UNIT LENGTH)

L= length

W=trace width

T=trace height

The Volume Resistivity of PWB Copper FOIL (ρ) is: 1.7241E-6 Ω-cm or 0.678790 micro-ohm

Temperature Coefficient of Resistivity (TCR) of Copper is: +3930 ppm/C ( NB: A POSITIVE TCR WHERE INCREASING TEMPERATURE RESULTS IN AN INCREASE IN RESISTANCE.TCR IS TYPICALLY SPECIFIED AT 20 DEGREES C. (SEE EQUATION BELOW AND CLICK IMAGE BELOW TO ENLARGE)

Picture
CLICK IMAGE TO ENLARGE