2. Control

2.1 Sensors

We'll just mention the components used for air-handling regulation.

• Thermostats

The bimetallic strip (figure 21 ), which is the sensitive element, is made up of two metal parts that expand differently under the effect of heat. One of these two metals is usually invar, which has a very low coefficient of expansion. As a result, the bimetallic strip bends when subjected to either heat or cold. It makes or breaks the electrical circuit by means of fixed and moving contacts.

• Temperature...