Fragrance diffuser having stepped power levels

A fragrance dispenser adapted for use with an expendable cartridge means for emitting a fragrance into the air when heated, said cartridge means having a predefined expected useful life, said fragrance diffuser comprising:

• housing means for receiving and containing said cartridge means;
• heater means for providing electric heating of said cartridge means in response to electric power;
• timer means for indicating when a predetermined period of time of operation of said heater means has lapsed, said timer means operating independently of temperature;
• means for partially reducing said electric power applied to said heater means;
• means for automatically controlling said heater means and said power reducing means in response to said timer means such that the amount of heat provided to said cartridge means is increased after said predetermined period of time of operation has lapsed.

In a fragrance diffuser having an electric heating element and a replaceable fragrance-bearing cartridge, said cartridge having a limited useful life, the method of adjusting the fragrance level over the life of said cartridge comprising the steps of:

• (a) heating the cartridge to a first temperature level;
• (b) providing a first timing signal upon the expiration of a first period of time;
• and
• (c) heating said cartridge to a second temperature level which is higher than said first temperature level in response to said first timing signal.