The voltage transformer is a transformer with an iron core. It consists of one or two coils, core and insulation.
When a voltage is applied to U1 in a winding, produces a magnetic flux in the core diameter, according to the law of electromagnetic induction in two winding generates a two voltage U2. Changing the number of turns of one or two windings can produce different primary voltage and two voltage ratio, which can form voltage transformer with different ratio. The voltage transformer high voltage into low voltage, according to the proportion of 100V, a voltage transformer is connected in a system, the two side connected measuring instrument and relay protection; mainly electromagnetic (capacitive voltage transformer is widely used), otherwise non electromagnetic, such as electronic type photoelectric type.