An isolation transformer mainly consists of two or more windings. These windings are wrapped around the same iron core, and there is no direct electrical connection between the windings. Usually, there are a primary winding and a secondary winding. When an alternating voltage is applied to the primary winding, due to the action of the alternating current, an alternating magnetic field will be generated in the iron core of the transformer. According to the principle of electromagnetic induction, the alternating magnetic field in the iron core will induce an electromotive force in the secondary winding, thus realizing the transformation of voltage. Meanwhile, since there is no direct electrical connection between the primary and secondary windings, the electrical isolation between them can effectively block direct - current and low - frequency noise.