"Vaiseshika" Precision Kelvin-Cum-Wheatstone Bridge Type : 9405
Description
"VAISESHIKA" Kelvin-cum-Wheatstone
Bridges Type : 9405 are important instruments in the
measurement of resistance as low as 0.1 Micro ohms to highest
value of 1 ohm.
Manganin has the quality of very low temperature co-efficient
which is a critical parameter for resistance standards
manufacturing. Kelvin cum Wheatstone Bridge
9405 is also constructed with manganin coils & sheet.
Phosphor Bronze Silver plated switches have been used to
minimise the residual resistance error. Four standard decade
dials, ratio selector & plug keys facilitate accurate null
detection.
User can easily
change over from Kelvin section to Wheatsone Bridge section
& vice-a-versa with the help of a selector switch.
KELVIN BRIDGE
SECTION
Range of Measurement
: 0.1 micro-ohm to 1 ohm
Accuracy
:below 0.0001 ohm0.2% :0.0001 to 0.01 ohm0.1% :above 0.01 ohm0.05%
+ 1 step of lowest decade dial
Reference Resistance
Standards
:0.001 ,0.01,1 and 1.0 ohm
Dividing
Ratio
:1 , 10 , 100 and 1000 ohm
Multiplying Ratio
:0.1 x 1, 1.0 x10, 10 x10 and 100 x10 ohmin shape
of Standard Decade Resistors.
WHEAT STONE BRIDGE
SECTION
Range
:1
ohm to 1.0 Megaohm
Accuracy
:1 ohm to 100.0K 0.1% :above 100.0K
1.0%
+/- 1 step of lowest deacde dial
Dividing and Multiplying Ratio
in Denominations
of
:1, 10, 100 and 1000 ohm
Variable
Arm
:Formulated by decade dials of 10x0.1, 10x 1, 10 x10 and 10 x
100 ohm.
PHYSICAL
PARAMETERS OF PRECISION KELVIN- CUM WHEATSTONE
BRIDGE
Construction
: Metal Cabinet
Panel
: Mica-hHylam
of high grade insulation
Dimensions
(in cms)
: 63 (L) x 39 (B) x 19 (H)
Weight (in kg.)
: 18
(approx.)
Accessories for Senior Kelvin Double Bridge:
Following accessories are requried with the Senior kelvin Double Bridge Type 9403 as support accessories to completer the measuremnt system. The Bridge become the complete measurement system in conjuction with the following accessories:
Spot Reflecting Galvanometer Type 9407A (Essential Assessory)
The Spot Reflecting Galvanometer will serve as a null detector to obtain the balance point in the circuit. The instrument is housed in a black bakelite case with lamp and scale arrangement for providing moving spot on the calibrated scale. The galvanometer resistance is of the order of125 ohms. The critical damping resistance will be1000 ohms and the galvanometer will be working on 220 volt AC
High Amperage DC Souece 9400E
This galvanometer is used for null detection. The sensitivity of the galvanometer is approximately 5 microvolt per mm. A moving light spot provides visual detection of the null point. The movement of the galvanometer is protected against shocks and vibrations. Clamping facility is provided to safeguard the moving coil against jerks and jitters during transit.Different shunts in the order of 1/0, 1/100, 1/1000 and 1 are incorporated in the Spot Reflecting Glavanometer to control the sensitivity of the galvanometer.Lamp and scale arrangement is built-in for spot null detection.
Code 9400 B : 0 to 30 Amp. suitable for Bridge Type 9403
Code 9400 C : 0 to 10 Amp. suitable for Bridge Type 9404
Code 9400 D : 0 to 50 Amp. suitable for Bridge Type 9405
Conductivity Attachment Type 9400E
This attachment is useful in the determination of specific resistance of a metal rod or metal sheet. Resistance per unit length of a sample can be measured with this attachment. Binding post teminals are provided which can hold the rod of 1/2" dia to 42 SWG Wire. The distance between two potential contacts is 50 cm.
Current Reversing Switch Type 9400F The direction of current is reversed in a Kelvin Bridge during the course of measurements. Current reversal is necessary to eliminate the errors due to thermo.e.m.f. This current Reversing Switch is a rugged device for the purpose.
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