A FILAMENT CONTROLLER

摘要

A control device (70) is disclosed for controlling a power supply (10) arranged to supply electrical power to a filament (Ra), the temperature of the filament (Ra) being non-linearly dependent on power supplied to the filament (Ra). The control device (70) is arranged to receive temperature control instructions and to control the power supply (60) such that the temperature of the filament (Ra) is controlled in accordance with the instructions. The control device (70) is also arranged to take into account the non-linear relationship between the filament temperature and power input into the filament (Ra) so as to control the filament temperature in accordance with the instructions. The temperature control instructions are a function of a detected change in filament temperature and the control device (70) controls the temperature of the filament (Ra) such that the life of the filament is prolonged.