Electrical Engineering ⇒ Topic : Applications of hot-wire voltmeter

Applications

(1) Hot-wire instruments are particularly useful for a.c. measurements and are as a rule cheaper than instruments based on dynamometer principle.

(2) Hot-wire instruments are used for high-frequency alternating currents (e.g., in wireless work) because the inductance of the hot-wire is very small. Dynamometer or moving-iron instruments are unsuitable at such high frequencies.

(3) Hot-wire ammeters are not, however, as accurate as dynamometer ammeters, and must be calibrated by comparison with a d.c. ammeter, say of the moving-coil type.