The goal of this lab is to measure the temperature coefficient
of resistivity **a** for a copper resistor.

If you make a graph with

- resistance on the y-axis
- temperature change (T - To) on the x-axis

Recall the manner in which resistance changes with temperature:

R = Ro * [ 1 + a*(T-To) ]We can write this as

R = Ro + (Ro*a)*(T-To)

When you make a graph of resistance **R** versus temperature
change **T-To**, you are graphing this equation.

- When temperature change equals 0, that is,
**T = To**, then the data shows the y-intercept. That is the value of the resistance at the reference temperature,**Ro**. So the point at which the data cross the y-axis is**Ro** - The slope of the line is the combination
**Ro*a**in the equation above.

First, determine the value of the resistance at reference temperature
**Ro** by looking at the y-intercept of your graph.
Second, measure the slope of your graph, which is **Ro*a**.
Finally, divide

slope Ro*a ------- = ------ = a Ro Roto find the value for temperature coefficient of resistivity

Compare your value to that for copper -- look in reference materials in the library or on the Internet to find it.

Copyright © Michael Richmond. This work is licensed under a Creative Commons License.