TB 9-4931-217-40
Table 3 . Sample Ratio Arm Worksheet
Resistance measuring system
indication (ohms)
Test instrument
range switch
Optimum
Measured
position
value
resistance value
Computed ratio
X1 = 1.00000 X 10-5
1 MILLIOHMS
1
1.000019
(X1)
X6b
X1 = 0.99999 X 10-4
2 OHMS
10
10.000100
(X2)
X6b
X3 = 1.00000 X 10-3
3 OHMS
100
100.0018
(X3)
X6b
X4 = 0.99999 X 10-2
4 OHMS
1,000
1,000.011
(X4)
X6b
X5 = 1.00000 X 10-1
5 KILOHMS
10,000
10,000.13
(X5)
X6b
6 KILOHMS
100,000
100,001.1
(X6a)
X6a = 0.99999
X6b
6 KILOHMS1
100,000
100,001.7
(X6b)
X6a = 1.00000 X 101
7 KILOHMS
10,000
10,000.11
(X7)
X7
X6a = 1.00000 X 102
8 MEGOHMS
1,000
1,000.012
(X8)
X8
X6a = 1.00000 X 103
9 MEGOHMS
100
100.0013
(X9)
X9
X6a = 1.000012 X 104
10 MEGOHMS
10
9.999990
(X10)
X10
X6a = 0.99998 X 105
11 GIGOHMS
1
1.000027
(X11)
X11
Use connection C of figure 1 for remaining switch positions (6 through 11).
1
a. Disconnect and remove TI from impedance measuring system.
b. Turn resistance indication dials and range switch through entire range at least 3 times.
8. Rheostat Arm Zero Resistance and Calibration
a. Performance Check
(1) Turn all resistance indicating dials to 0 (zero) and range switch to 11 GIGOHMS.
(2) Connect equipment as shown in figure 1, connection A.
(3) Measure and record lead and wiper arm resistance (zero resistance). Measured
resistance will not exceed 0.04 ohm.
(4) Turn resistance indicating dials to settings listed in table 4 and measure
resistance at each setting. Subtract zero-resistance value recorded in (3) above from each
resistance measurement. Difference will be within specified limits in table 4.