JAMB - Physics (2004 - No. 4)
For semi conductor to have negative temperature coefficient of resistance implies that
their resistance decrease with temperature
The resistance increase with temperature
their resistance is constantly changing with temperature
they have electrons and holes at high temperature
คำอธิบาย
Temperature coefficient of resistance is given by
And for metals where resistance increase with temperature rise, temperature coefficient of resistance is positive; on the other hand in semi conductors, where resistance decrease with temperature rise, temperature coefficient of resistance is negative.
| α = | Increase in resistance per oC rise in temp. |
| __resistance at 0oC |
And for metals where resistance increase with temperature rise, temperature coefficient of resistance is positive; on the other hand in semi conductors, where resistance decrease with temperature rise, temperature coefficient of resistance is negative.