A Precise Active Voltage Divider for Power Measurements

In the field of power measurements, a precise, measurable copy of the test quantity "voltage" must be generated which can then be fed to the multiplying device properly. An inductive divider allows this copy of the voltage to be obtained at power frequencies (50 Hz) with a long-time stability and measurement uncertainty of approx. 10^-6 in the divider ratio according to magnitude and phase. It is also possible to use a resistive divider. In the following it will be shown, how a broad-band, unloaded phase-accurate resistive divider can be set up by means of amplifying techniques as well as guarding and shielding techniques respectively