Supports the calibration of clamp-type current meters The 50 Turn 5500A/COIL is used as a tool for calibrating clamp type current meters that operate by two different principles ¾ as current transformers (AC only), and by the Hall Effect (Both AC and DC). It is impractical to calibrate 1000A rated current clamp meters using a 1000A source. However, by using the 50 turns of the 5500A/COIL in conjunction with a current calibrator you can effectively multiply the current of the current calibrator by a factor of 50 to support the calibration and verification of these clamp-on current meters.