TB 9-6625-1493-35
Figure 8. Microvolt potentiometer - rear view.
24. Range Accuracy
a. Performance Check
(1) Connect equipment as shown in figure 9.
(2) Set TI switches as listed in (a) through (c) below:
(a) INT-EXT to INT.
(b) ELECTRONIC GALVANOMETER switch to CHECK.
(c) RANGE to 5 V.
(3) Disconnect lead from dc voltage divider output HIGH terminal.
(4) Turn REFERENCE EMF COARSE, MED, and FINE controls fully ccw.
(5) Set ELECTRONIC GALVANOMETER switch to 30 NA and adjust 0 variable
control for a 0 indication on NANOAMPERES meter. Do not change variable control
setting.
(6) Set ELECTRONIC GALVANOMETER switch to CHECK and RANGE switch
to 50 MV.
(7) Reconnect lead to dc voltage divider output HIGH terminal.
(8) Set dc voltage divider dials to .100000.
(9) Set calibrator for a 0.5 V dc output.
(10) Adjust REFERENCE EMF COARSE, MED, and FINE controls for an
indication of 5 on EMF DC meter.
(11) Set ELECTRONIC GALVANOMETER switch to 3 A, 300 NA, and 30 NA,
respectively, while adjusting REFERENCE EMF COURSE, MED, and FINE controls
until NANOAMPERES meter indicates null. Digital multimeter/multimeter will indicate
between 0.49977 and 0.50023 V.
(12) Set ELECTRONIC GALVANOMETER switch to CHECK.
