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Two resistors of equal magnitude R, with temperature coefficients of resistance alpha1 and alpha2 respectively, are connected in parallel. What is the approximate temperature coefficient of the parallel combination?

1. 2*(alpha1 + alpha2)
2. alpha1*alpha2/(alpha1 + alpha2)
3. (alpha1 - alpha2)/2
4. (alpha1 + alpha2)/2

Correct answer: (alpha1 + alpha2)/2

Solution

To first order, equal parallel resistors give an effective coefficient (alpha1 + alpha2)/2.

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