In AC circuits, for measuring large voltages a specially constructed accurate ratio Potential Transformers are used. Their function is to reduce the supply Voltage to a value small enough to be easily measured with standard low range AC instruments of moderate size and capacity. The advantages of using Potential Transformers for range extension of AC meters are many fold.

In AC circuits, for measuring large voltages a specially constructed accurate ratio Potential Transformers are used. Their function is to reduce the supply Voltage to a value small enough to be easily measured with standard low range AC instruments of moderate size and capacity. The advantages of using Potential Transformers for range extension of AC meters are many fold.