A New Bridge Network for Alternating-Current Magnetic Measurements

The paper describes a transformer-coupled bridge suitable for magnetic measurements in the entire audio-frequency range. The bridge is simple in operation and the earth-capacitance effects of the components are extremely small. It does not require elaborate multiple screening of components or any special form of earthing, e.g., Wagner Earthing. It can be adapted easily for measurements under incremental conditions, i.e., under superposed direct and alternating flux in the core. Selected experimental results are included in the paper to show the flexibility of the bridge for the measurements of core-loss and ac permeability between 150 c/s and 20 kc/s with a single set of precision grade laboratory equipment, viz., two units of decade resistor boxes and a decade capacitor box.