noun
ammeter; amperemeter
Technical term for an instrument that measures electric current in amperes.
回路に電流計を直列に接続して電流を測定する。
Connect an ammeter in series with the circuit to measure the current.
テスター is a general-purpose multimeter that can measure current, voltage, and resistance, while 電流計 is specifically for current.
Compound of 電流 (electric current) and 計 (meter, gauge).