When used to control reactive (inductive or capacitive) loads, care must be taken to ensure that the TRIAC turns off correctly at the end of each half-cycle of the AC in the main circuit. TRIACs can be sensitive to fast voltage changes (dv/dt) between MT1 and MT2, so a phase shift between current and voltage caused by reactive loads can lead to a voltage step that can turn the thyristor on erroneously. An electric motor is typically an inductive load and off-line power supplies—as used in most TVs and computers—are capacitive.