POWER SUPPLY DEVICE

PROBLEM TO BE SOLVED: To provide a power supply device capable of achieving low voltage while preventing size increase and cost increase even when a voltage required for load is low.SOLUTION: A power supply device 100 comprises: a current transformer 1; a capacitor 2; a rectification circuit 4; voltage adjustment means 5; and a smoothing capacitor 6. An AC power supply 10 is connected to the primary side of the current transformer 1, and a load 20 is connected to the secondary side of the current transformer 1. On the primary side of the current transformer 1, a capacitor 2 is connected in series to a primary coil 1a of the current transformer 1. On the secondary side of the current transformer 1, the rectification circuit 4 is connected in parallel to a secondary coil 1b of the current transformer 1, and the voltage adjustment means 5 and the smoothing capacitor are connected in parallel to the rectification circuit 4. When an AC power supply 10 causes AC current to flow to the primary coil 1a of the current transformer 1, an inductive voltage occurs in the secondary coil 1b. This inductive voltage is rectified by the rectification circuit 4 and smoothed by the smoothing capacitor 6. The smoothed voltage is adjusted to a prescribed voltage by the voltage adjustment means 5 and supplied to the load 20.