Matrix - Electronic Circuits and Components | Resistors / Examples: Resistance and Temperature

Example 1:

A resistor has a temperature coefficient of 0.002/°C.

If the resistor has a resistance of 2.2kΩ at 0°C, determine its resistance at 60°C.

Now R_t = R₀(1 + αt) thus R_t = 2.2kΩ x (1 + (0.002 x 60))

Hence R₆₀ = 2.2 x (1 + 0.12) = 2.2 x 1.12 = 2.464kΩ

Example 2:

A resistor has a temperature coefficient of 0.0008/°C.

If the resistor has a resistance of 470Ω as 20°C, what will its resistance be at 70°C?

First we must find the resistance at 0°C. Re-arranging the formula for R_t gives:

Now:

R_t = R₀(1 + αt) thus R₇₀ = 470 x (1 + (0.0008 x 70))

Hence: R₇₀ = 470 x (1 + 0.056) = 470 x 1.056 = 496.3Ω

Example 3:

A resistor has a resistance of 20Ω at 0°C and 22Ω at 100°C.

Determine the temperature coefficient of resistance.

First we need to make a the subject of the formula.

R_t = R₀(1 + αt):

Now: 1 + αt =

thus: αt = - 1

Hence: α = = 0.001Ω/Ω/°C