The Fluke 5220A, Transconductance Amplifier, that lets you calibrate AC or DC current meters and shunts, as well as the current functions of digital multimeters and VOMs that measure up to 20 amperes. Designed to be controlled by the 5100B or 5101B Calibrator, the Fluke 5220A may also be driven by another source such as the 5200A.