Controlling humidity and moisture is critical in many equipment, especially the ones which are in critical applications and need to serve reliably for long durations of time. Resistors can be used as small heaters for localised heating to control the temperature around critical devices to prevent condensation. These can be small resistors as air heaters mounted on PCB’s, or small aluminium housed resistors which can be used to heat any surface, or specially designed heaters with attached fans to heat a cabinet to required temperature to eliminate moisture and condensation.