Fluke 825A - Page 13

SECTION Il
OPERATING INSTRUCTIONS
2-1. CONTROLS, TERMINALS, AND INDICATORS
The
location,
circuit
symbol,
and
a
functional
descrip-
the
825A
Precision
Differential
DC
Voltmeter
may
be
tion
of
external
controls,
terminals,
and
indicators
on
found
in
figure
2-1.
CONTROLS
TERMINALS
CIRCUIT
TS . LOCATION SYMBOL
INDICATORS
Input terminals Front panel J1, J3
Chassis ground Front panel J2
terminal
Power toggle Front panel S1
switch
OPERATE- Front panel 54
CALIBRATE
switch
CALIBRATE Front panel
control
RANGE Front panel
switch
Figure 2-1. CONTROLS, TERMINALS,
FUNCTIONAL DESCRIPTION
Provided for connecting DC voltage to be
measured.
Provided for grounding purposes. А 0. 47 uf
capacitor
is
connected
from
the
lower
input
bind-
ing post to the chassis ground post. The upper
input post should never be connected to the chassis
ground post. Since the instrument is equipped
with a three-wire line cord with the third wire
fastened to the chassis, the external circuit
should be checked for conflicts in grounding before
connecting
lower
input
binding
post
(middle
post)
to the chassis post.
Applies
AC
line
voltage
to
the
primary
circuit
of
the
power
transformer.
Remains inthe OPERATE position at alltimes except |
when it is necessary to calibrate the internal 500 volt
DC reference supply. When held in the CALIBRATE
position, a representative sample of the reference
voltage is comparedto the voltage of an internal stan-
dard cell, or Zener diode for the /AG models, and
any difference is indicated on the meter.
Varies the output of the 500 volt DC reference
supply. When the OPERATE-CALIBRATE switch
is held in the CALIBRATE position, the reference
supply is accurately set by adjusting the CALI-
BRATE control for zero meter deflection.
Selects desired voltage range. Full scale voltage
ranges of 500, 50, 5, and 0.5 volts are available.
AND INDICATORS. (Sheet 1 of 2)
2-1