Disk drive with selectable power source for heater in a slider

A disk drive comprising:

• a slider with a heater in an electrical circuit;
• an adjustable power control device in the electrical circuit connected in series with the heater to supply variable power to the heater;
• at least first and second voltage sources;
• a programmable switch in the electrical circuit which switchably connects at least a first or second path into the electrical circuit, the first path resulting in a first voltage being applied across the heater and the adjustable power control device in series and the second path resulting in a second voltage being applied across the heater and the adjustable power control device in series and the second voltage being lower than the first voltage;
• and
• a control system which controls the programmable switch to apply the first voltage across the heater and the adjustable power control device when high power is needed for the heater and to apply the second voltage across the heater and the adjustable power control device in series when high power is not needed for the heater.