«Hasler». Switzerland. 1900
Instrument for measuring current in amperes. The ammeter scale is calibrated in microamperes, milliamperes or kiloamperes in accordance with the limits of the measuring instrument. The ammeter is placed in-sequence in that section of the electrical circuit in which the current is to be measured. To increase the detection accuracy, a shunt or transformer may be used. (An example of an ammeter with the transformer is the current clamp transformer).