To control the moisture content of linen leaving a drying ironer, this content
is measured by means of a sensor (18). The measurement signal is then transmitted
to a variable gain amplifier (30). A circuit (32) automatically adjusts
this gain so that the signal leaving the amplifier (30) is non-saturated.
This gives instant control of linen moisture content irrespective of the moisture
content of the items of linen entering the machine.
