A contact arm and three metal studs mounted on a bakelite base with three brass terminals. The centre terminal is common a connection to arm and the two other terminals are connected to other studs.

A dia sweeping brush contact, one for the main central contact and other for individual resisters, made from hardened copper phosphor bronze strips inforced by a spring strip are held in place by a rotating bakelite knob. The values of resisters are engraved on the vulcanite plate indicated by the index on the edge of knob at each click stop. Constantan wire, double wound resisters are dipped in boiling wax for constant values. Accuracy 0.1 % Ten steps of 0.1 ohm total 1 ohm, or Ten steps of 1 ohm total 10 ohms.

For DC measurements, designed for use in schools, colleges and technical
institutions. All Meters are housed in moulded dust proof cases, with zero adjuster accessible front and have connections on back.

AMMETERS
Moving coil for D.C. measurements. Any single range 0-1, 1.5, 3, 5, 10 mA.

MILLI-AMMETERS
Moving coil for D.C. measurements. Any single range 0-1, 5, 10, 25, 50, 100, 250, 500 mA.

MICRO-AMMETERS
Moving coil for D.C. measurements. Any single range 0-50, 100, 150, 100, 200, 250, 500 µA.

VOLT METERS
Moving coil for D.C. measurements. Any single range 0-1, 1.5, 3, 5, 10, 25, 50, 100, 250, 300 volts.

MILLI-VOLT METERS
Moving coil for D.C. measurements. Any single range 0.25, 25, 50, 100, 150, 250, 500 mV.

GALVANOMETERS
Moving coil for D.C. measurements.
Range : (a)  1-0-1 mA.   (b) 35-0-35 mV.   (c) 3.5-0-3.5 mA.

AMMETERS
Moving Iron, A.C./D.C. Any single range 0-1.5, 3, 5, 10 Amps.

An alloy of manganese, nickel and copper, having a low temperature coefficient. This wire is particlarly suited to constuction of resistence coils etc. or any application where accuracy of ohmic value is the important factor and electrical loading is low.

	Diameter in mm	Nearest S.W.G.	Mass per Reel
a)	0.90	20	50gms
b)	0.71	22	50gms
c)	0.56	24	50gms
d)	0.45	26	50gms
e)	0.40	28	50gms
f)	0.31	30	50gms

The electrically oxidised eureka wire is wound on perfectly round 43mm dia porcelain pipe according to length required. The vulcanite/Aluminium hexagonal/round supports light the pipe on each side with a rod and nuts. The guide rod carrying the contact block is lightened with screws to the projection of the supports and carry the third terminal which permits the instrument to be used in any step. The contact block carries smooth phosphor bronze brush contacts. The instrument is perfectly insulated. < /tr>

	Max Current	Max Resistance	Tube Dia	Tube Length
a)	6.5	4.4	43mm	200mm
b)	5.0	11	43mm	200mm
c)	4.2	12	43mm	200mm
d)	3.3< /td>	16	43mm	200mm
e)	3.3	27	43mm	300mm
f)	2.3	56	43mm	300mm
g)	1.6	50	43mm	300mm
h)	1.6	100	43mm	250mm
i)	0.8	160	43mm	150mm
j)	0.8	240	43mm	200mm
k)	0.3	1700	43mm	200mm
l)	0.3	2850	43mm	300mm
m)< /td>	8.2	2	56mm	150mm
n)	8.2	4.5	56mm	250mm