With interchangeable scales. A versatile instrument & demonstration meter that can be converted to an a.c., or d.c. voltmeter or ammeter with selection of various ranges for each mode. With a high quality moving coil, spring controlled movement with full scale deflection of 5 mA or 100 mV d.c. The long pointer has a spade end and is clearly visible from a distance. Fitted in case with glass front and back. The instrument can be used with different dials to give different voltage & current ranges. All dials are interchangeable & each has a plug coupler to fit the instrument. A zero adjuster allows the instrument to be used for centre zero dials. One dial of range 50-0-50 mV d.c. is supplied with the instrument.
It is used to compare currents or to determine Value of "H" (Horizontal component of earth field) if current is known. It consists of a Bakelite ring dia. 16cm approx. wound with 3 coils of 2, 50 and 500 turns of insulated copper wire. Compass Box is mounted at center of the ring and both can rotate independent of the base. Provided with terminals to put either of the three coils in circuit at a time. Base is supported on three leveling screws.