19-03-2014, 12:25 PM
SENSORS and TRANSDUCERS
SENSORS.PDF (Size: 973.7 KB / Downloads: 64)
Thermal Energy Domain - Physics
k We are considering thermal transducers that are used for converting
thermal information into electrical signals.
Basic mechanisms relevant for our discussion:
Seebeck effect
Peltier effect
Thomson effect
Thermoresistance
Seebeck coefficient describes a bulk effect, determined by the follow ing
effects:
Temperature difference generates a difference in Ferm i level
Bandgap distance changes with temperature
The gradient of charge carriers changes for n and p type as a function of
temperature
Diffusion coefficient is a function of temperature
Charge carriers move from the heated side to cold side - thermodiffusion
Electric field will be generated due to the transport of charge carriers
Seebeck effect is used mainly