IET Labs, Inc. 1864-1644, User And Service Manual

Page: 21 / 46

OPERATION
1864-1644 Positive Polarity Megohmmeter
11
3.3 Output Jack
The OUTPUT jack (J105) on the rear panel makes
accessible a dc voltage that is directly proportional to
the reciprocal of the meter reading, that is, the highest
value is at the 0.5 scale reading and the lowest value
is at
∞ . The output voltage for a particular multiplier-
switch setting can be calculated by
V
OUT
= 0.02
x
V
TEST
x
R
RANGE
R
X
where V
TEST
is the TEST VOLTAGE setting, R
RANGE
is the lower value for a particular multiplier-dial set-
ting (100k for the 1 M/100 k range) and
R
x
is the value
of the resistance being measured.
The output can be stored in a data fi le for plotting,
display, or analysis. It can also feed the user’s go/
no-go indicator. The full-scale voltage value for any
test voltage can be calculated from the
V
out
formula
using 0.5 times the measurement range as the R
x
value. These values are available on the 1864 along
with the other levels that can be set with the variable
TEST VOLTAGE switches (see table 3-1).