Question: TCR (Temperature coefficient of resistance)

Mumbai University > Electronics Engineering > Sem 8 > MEMS Technology

Marks: 3M

modified 2.9 years ago by gravatar for Juilee Juilee2.3k written 2.9 years ago by gravatar for Hetal Gosavi Hetal Gosavi70
  • Resistance values for conductors at any temperature other than the standard temperature on a specific resistance must be determined by the formula

    R= Rref[1+α(T-Tref]


    R= conductor resistance at temperature T

    Rref= conductor resistance at reference temperature Tref

    .α= temperature coefficient of resistance TCR for conductor material

    T= Conductor temperature in degrees

    Tref= reference temperature that is specified for conductor material

  • The TCR symbolizes the resistance change factor per degree of temperature change
  • All materials have specific resistance and changes according to the temperature
  • For pure metal the TCR is positive, ie the resistance increases with increase in temperature
  • decreases with increase in temperature
  • For alloys the TCR is zero ie the resistance hardly changes at all with variation in temperature.
  • In any material the internal resistance will change as the temperature changes.
  • The rate of resistance change is based on temperature and is referred to as TCR.
  • It is denoted in units of Ppm/C and determined from the resistance changed from some reference temperature and change in temperature
  • One advantage of poly Si over Cryst. Si is its reduced TCR
  • The TCR for Poly Si and crystal is approx 0.04%/degree C. compare to 0.14%/degree C for Cryst. Si.
  • The deposition process and type of dopant can alter the sign of TCR
  • Emitter type Poly si have a TCR of -0.045%/degree C
  • Resistance with positive TCR are used in compensating the –ve temp dependence of piezoresistance sensor.
written 2.9 years ago by gravatar for Hetal Gosavi Hetal Gosavi70
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