from the heating devices 30 the control algorithm whereby the power control 10 modulates the power output therefrom may be adapted to provide electrical power to the heating devices in a non linear and or discontinuous manner as can be seen in fig8 heating devices 30 such as a heat lamp will for a given applied voltage yield a power output that is non linear with respect to the power voltage input to the heating device 30 note that the output of a typical heating device 30 is shown in the figure as line 31 b accordingly where it is desirable to ensure that the output of the heating devices 30 be linear as shown by line 31 a which represents an ideal linear power output the voltage applied to the heating devices 30 by the power control 10 will be varied non linearly over the control band in order to drive a linear output for the heating devices 30 it is to be understood that the function used to calculate the percent power output of the power control 10 would be specific to each heating device 30 resistive heating devices 30 such as heat pads are more generally linear in their response and accordingly the function used to calculate the power to be applied to a heat pad would be linear in nature as heat lamps vary in their output as shown in fig8 the function used to determine the output of the power control 10 would more closely approximate.