The AM503B AC/DC Current Probe Amplifier is the heart of the AM503S System. The AM503B amplifies and sums the voltage outputs from the transformer and Hall Effect device and outputs it to the measurement instrument. It also provides the Hall Effect Device bias voltage and a reverse "bucking" current which resists saturation of the A6312/A6302/A6303 Current Probe core. All functions are microprocessor controlled, and the AM503B uses bright, easy-to-read LEDs to display current/Division settings which are controlled with up/down push buttons. A single push button provides both Degauss and auto-balance functions.