Ammeter

The present invention relates to the technical field of current measurement, and discloses an ammeter which includes: a combined type comparator, a first direct current comparator, a bipolar active compensation transformer, an AC transformer, a first signal conversion unit, a second signal conversion unit, a third signal conversion unit, a fourth signal conversion unit, a first analog-to-digital conversion circuit, a second analog-to-digital conversion circuit, an DSP and a power supply module. The combined type comparator includes a second direct current comparator, a power amplifier, a Hall signal amplifier, four Hall elements, and an iron core which have four air gaps formed through incision. The four Hall elements are respectively arranged in the four air gaps. The four Hall elements are connected with the Hall signal amplifier. The Hall signal amplifier is connected with the power amplifier. The power amplifier is connected with a first secondary winding of two secondary windings of the second direct cur