A power regulator 130 includes a power input line 181, a primary winding connected to the power input line 181 and wound on a core, a secondary winding, at least part of the secondary winding being in common with the primary winding, at least one tap 132, 133, and 134 connected to the primary winding at a predetermined position thereof to specify respective numbers of turns of the primary winding and the secondary winding, at least one switch S1, S2, and S3 having one end connected respectively to the at least one tap 132, 133, and 134 and another end connected to a common line 183 to change the respective numbers of turns of the primary winding and the secondary winding, and an output line 182 for outputting power that the secondary winding generates as the secondary winding is excited by the primary winding, wherein the respective numbers of turns of both the primary winding and the secondary winding are determined as one of the at least one switch S1, S2, and S3 is closed.