CPD Dynamics Ltd
Assess your understanding of Climatic Testing
1. A three-term controller is:
(a) a device which displays temperature, humidity and pressure.
(b) a controller which provides 3 set points, 3 ramps and 3 dwells in a given period of time.
(c) a method of compensation for the resistance of the leads in a temperature measuring circuit.
(d) a mathematical system which provides the most accurate control of a climatic chamber.

2. Fluctuations in climatic chamber temperature readings can be minimised by using:
(a) high thermal response sensors.
(b) low thermal response sensors.
(c) long, small diameter sensors.
(d) four-wire platinum resistance thermometers.

3. A wet and dry bulb psychrometer is used to measure:
(a) temperature changes with altitude.
(b) relative humidity.
(c) air pressure during an anticyclone.
(d) saturation vapour pressure.

4. The variation of electrical resistance with temperature for a PRT can be written in the form of:
(a) a higher order polynomial.
(b) a linear equation.
(c) a logarithmic equation.
(d) a parabolic equation.

5. Using the psychrometric chart below, estimate the relative humidity level in %RH given a dry bulb temperature reading of 25 oC. and a wet bulb temperature reading of 20 oC.