A hair styling apparatus comprising: a body having at least one arm bearing a hair styling heater (26, 956) for heating hair to be styled; a temperature sensor (944, 954) arranged to sense a temperature of the hair styling heater (26, 956) and to generate an electrical temperature sense signal that depends on the sensed temperature of the hair styling heater (26, 956); and a power supply unit comprising a magnetic energy transfer element (223, 923), an AC input coupled to a first side of the magnetic energy transfer element (223, 923), a heater drive output coupled to a second side of the magnetic energy transfer element (223, 923) and to the hair styling heater (26, 956) to power said hair styling heater (26, 956), and a power controller (222, 922, 952) configured to regulate the heater drive output, wherein the magnetic energy transfer element (223, 923) comprises a transformer having a primary winding on the first side and a secondary winding on the second side, wherein the primary winding is coupled to the AC input, and wherein the secondary winding is coupled to the hair styling heater (26, 956); wherein the power controller (222, 922, 952) is coupled to the temperature sense signal; wherein the power controller (222, 922, 952) is configured to regulate the heater drive output of the power supply so as to control the temperature of the hair styling heater (26, 956) responsive to the temperature sense signal; wherein the power supply further comprises a primary side switch coupled to the primary winding, and wherein the power controller (222, 922, 952) is configured to receive the electrical temperature sense signal and to regulate the heater drive output responsive to the temperature sense signal by controlling switching of the primary side switch coupled to the primary winding. a body having at least one arm bearing a hair styling heater (26, 956) for heating hair to be styled; a temperature sensor (944, 954) arranged to sense a temperature of the hair styling heater (26, 956) and to generate an electrical temperature sense signal that depends on the sensed temperature of the hair styling heater (26, 956); and a power supply unit comprising a magnetic energy transfer element (223, 923), an AC input coupled to a first side of the magnetic energy transfer element (223, 923), a heater drive output coupled to a second side of the magnetic energy transfer element (223, 923) and to the hair styling heater (26, 956) to power said hair styling heater (26, 956), and a power controller (222, 922, 952) configured to regulate the heater drive output, wherein the magnetic energy transfer element (223, 923) comprises a transformer having a primary winding on the first side and a secondary winding on the second side, wherein the primary winding is coupled to the AC input, and wherein the secondary winding is coupled to the hair styling heater (26, 956); wherein the power controller (222, 922, 952) is coupled to the temperature sense signal; wherein the power controller (222, 922, 952) is configured to regulate the heater drive output of the power supply so as to control the temperature of the hair styling heater (26, 956) responsive to the temperature sense signal; wherein the power supply further comprises a primary side switch coupled to the primary winding, and wherein the power controller (222, 922, 952) is configured to receive the electrical temperature sense signal and to regulate the heater drive output responsive to the temperature sense signal by controlling switching of the primary side switch coupled to the primary winding.