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Examples: Resistance and Temperature

<^< Resistance and Temperature | Course Index | Positive Temperature Coefficient >^>(:nl:)

>>frame round<<Example 1:

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

If the resistor has a resistance of 2.2k&#937; at 0°C, determine its resistance at 60°C. >><<

>>id=example1 class=question margin=10px frame round<< Now R'_t_' = R'_0_'(1 + &#945;t) thus R'_t_' = 2.2k&#937; x (1 + (0.002 x 60))

Hence R'_60_' = 2.2 x (1 + 0.12) = 2.2 x 1.12 = 2.464k&#937; >><<

>>frame round<< Example 2:

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

If the resistor has a resistance of 470&#937; as 20°C, what will its resistance be at 70°C? >><<

>>id=example2 class=question margin=10px frame round<< First we must find the resistance at 0°C. Re-arranging the formula for R'_t_' gives:

Now:

R'_t_' = R'_0_'(1 + &#945;t) thus R'_70_' = 470 x (1 + (0.0008 x 70))

Hence: R'_70_' = 470 x (1 + 0.056) = 470 x 1.056 = 496.3&#937;

>><<

>>frame round<< Example 3:

A resistor has a resistance of 20&#937; at 0°C and 22&#937; at 100°C.

Determine the temperature coefficient of resistance. >><<

>>id=example3 class=question margin=10px frame round<< First we need to make a the subject of the formula.

R'_t_' = R'_0_'(1 + &#945;t):

Now: 1 + &#945;t =

thus: &#945;t = - 1

Hence: &#945; = = 0.001&#937;/&#937;/°C >><<(:nl:)(:table style="clear:both":)