Comment faire comment fabrique comment creer
In general, as the temperature of a material increases, most conductors increase in resistance, insulators decrease in resistance, whilst the resistance of some
special alloys remain almost constant.
The temperature coefficient of resistance of a material is the increase in the resistance of a 1Ω resistor of that material when it is subjected to a rise of temperature of 1◦C. The symbol used for the temperature coefficient of resistance is α (Greek alpha). Thus, if some copper wire of resistance 1Ω is heated through
1◦C and its resistance is then measured as 1.0043Ω then α=0.0043 Ω/Ω
◦C for copper. The units are usually expressed only as ‘per ◦C’, i.e. α=0.0043/
◦C for copper. If the 1Ω resistor of copper is heated through 100◦C then the resistance at 100◦C would be 1+100×0.0043=1.43Ω. Some typical values of temperature coefficient of resistance measured at 0◦C are given below:
(Note that the negative sign for carbon indicates that its resistance falls with increase of temperature.)
If the resistance of a material at 0◦C is known the resistance at any other temperature can be determined from:
In general, as the temperature of a material increases, most conductors increase in resistance, insulators decrease in resistance, whilst the resistance of some
special alloys remain almost constant.
The temperature coefficient of resistance of a material is the increase in the resistance of a 1Ω resistor of that material when it is subjected to a rise of temperature of 1◦C. The symbol used for the temperature coefficient of resistance is α (Greek alpha). Thus, if some copper wire of resistance 1Ω is heated through
1◦C and its resistance is then measured as 1.0043Ω then α=0.0043 Ω/Ω
◦C for copper. The units are usually expressed only as ‘per ◦C’, i.e. α=0.0043/
◦C for copper. If the 1Ω resistor of copper is heated through 100◦C then the resistance at 100◦C would be 1+100×0.0043=1.43Ω. Some typical values of temperature coefficient of resistance measured at 0◦C are given below:
If the resistance of a material at 0◦C is known the resistance at any other temperature can be determined from:
No comments:
Post a Comment