High-frequency high-voltage current measuring apparatus

A current meterage device includes a ring magnetic core, a secondary coil, an isolating layer and an amplification circuit. The ring magnetic core surrounds with a measured circuit; the secondary coil enwinds with the ring magnetic core; the isolating layer is actually to shield the secondary coil and ring magnetic core to block the static coupling between the secondary coil and measured circuit; an open mouth is made on the isolating layer to avoid the eddy current cost; the amplification circuit is connected with the secondary coil and amplify the current in secondary coil.