29 March 2020

Advantages and disadvantages of temperature sensor | thermocouple, RTD, thermistor

The sensor which senses changes in temperature known as a temperature sensor. This page covers the advantages and disadvantages of a temperature sensor. This article covers the advantages and disadvantages of thermocouple, RTD and Thermistor.

Advantages and disadvantages of temperature sensor | thermocouple

Advantages or benefits of thermocouple:

  • Very wide temperature range about -200oC to +2500oC
  • Fast response time
  • They are a simple construction
  • Low initial cost
  • Durable
  • Easy to read has a clear screen and good scale
  • Quick response for any temperature changes
  • Precision accuracy in temperature measurement
  • It is not easily broken good durability
  • Good to be used temperature variation measurement with below 1 cm distance range
  • Available in small sheath sizes
  • Not required bridge circuit
  • Good accuracy
  • Does not required bridge circuit
  • Good reproducibility
  • High-speed response
  • They are rugged
  • They are a self-power active device
Disadvantages  or drawback of thermocouple:
  • Not as stable as RTD
  • Recalibration is difficult
  • More susceptible to RFI/EMI
  • They are nonlinear
  • It is used for only temperature measurement only
  • They have a low output voltage
  • Less sensitivity
  • They require a reference for operation
    The stray voltage pick up is possible
  • As output voltage is very small so it needs amplification
  • Decreased accuracy comparing to RTD
  • Difficult to verify
  • Require expensive TC wire from the sensor to recording device
  • The cold junction and lead compensation is essential

Advantages and disadvantages of temperature sensor | RTD

Advantages or benefits of RTD:
  • Very stable output
  • Most accurate
  • Linear and predictable
  • High accuracy
  • High repeatability
  • Good precision
  • Low Drift 
  • More linearity compare to a thermocouple
  • No special wire required for installation, easily install and update
  • It is available for in wide range
  • It can be used to measure differential temperature
  • No necessity of temperature compensation
  • Stability maintained over a long period of time
  • They are suitable for remote indication
  • Easy to verify and recalibrate
  • RTD does not require a special extension cable
Disadvantages or drawback of RTD:
  • High initial cost
  • Low sensitivity 
  • It requires a more complex measurement circuit
  • Large bulb size
  • Low absolute resistance
  • Current source needed
  • Less rugged in a high vibration environment
  • A bridge circuit is needed with power supply
  • Shock and vibrations affect the reading
  • Point sensing is not possible
  • A circuit is little more complicated as it 34/4 wire measurement
  • Costlier as compared to other sensors like thermocouples
  • Slower response time than a thermocouple
  • More limited temperature range
  • Possibility of self-healing
  • Power supply failure can cause an erroneous reading
  • It can be avoided in industries for ranges above 650 deg. C
  • The RTD requires more complex measurement circuit

Advantages and disadvantages of temperature sensor | thermistor

Advantages or benefits of thermistor:
  • It is a small size
  • Highly sensitive allows them to work well over a small temperature range
  • They are more sensitive than other temperature sensors
  • Easy to use
  • They are fast in operation
  • It has good sensitivity in NTC region
  • Fast response over the narrow temperature range
  • Cost is low
  • Very responsive to changes in temperature
  • High accurate
  • Repeatable
  • It does not require contact and leads resistance problem not occurred due to large resistance
  • Options for customization
  • Easily interfaced to electronics instrumentation
  • it requires a standard two-wire connection system means they are compatible with many devices
Disadvantages or drawback of thermistor:
  • Thermistor need for shielding power lines
  • Extremely non-linear
  • Passive
  • The thermistor is not suitable for a large temperature range
  • The resistance temperature characteristics are nonlinear
  • Narrow working temperature range compared to other sensors such as RTD and thermocouple
  • More fragile as they are semiconductor devices
  • Susceptible to self-heating errors
  • The excitation for large temperature range
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