Select giving reasons the most suitable choice of temperatur

Select, giving reasons, the most suitable choice of temperature sensor for use in the following scenarios: Measuring the temperature of a printed circuit board in a computer. Measuring the temperature in a glass melting furnace that operates at temperatures of up to 1600 degree C. Reliable measurement of the temperature in a pharmaceutical process over the range 0 to 300 degree C and within plusminus 0.5 degree C. Measuring the water temperature in a dishwasher. Measuring the rate of change of temperature at a particular spot on the cylinder head on an internal combustion engine. Measuring temperature of the behaviour of metals at very low temperatures (123 to 70 K) in a cryogenics laboratory.

Solution

(a) .

Printed Circuit board generates less amount of heat and very compact in size .
From the available temperature sensors IC(Analog) or IC (Digital) sensors can be selected due to their advantages in cost linearity and digital output and thier range between -55 degrees Centigrade to +200 deg C.

(b).

Glass furnace generates very high temperatures of about +1600 degrees centigrade . Only temperature sensor which can with stand this is thermocouple ranging -267 deg C to +2316 deg C . Though it has less sensivity and complexity the range which it offers gives the best to use for this application.

(c)

In pharmaceutical process we require precise measurement hence we use Thermistors due to good sensitivity.
RTD (Resistance Temperature Detectors ) also hold good for this purpose but to choose between them the designer has to sacrifice either linearity or sensitivity depending on type of sensor . RTD provides good accuracy and lineriaty but its sensitivity is less compared to Thermistor.

(d)

A simple dishwasher doesnt require too much accurate and complex sensors. Hence for this application we use economically benefited sensor like the IC sensors whose Circuitry is simplest and highly economical of all.

(e)

Internal combustion engine application is required to calculate the temperature at a spot hence we use RTD (Resistance Temperature Detector ) where heat transfer takes place through convection.

(f)

For low temperatures only thermocouple sensors give the proximity range of such applications where the sensitivity is best and circutry can also be made simplex