TM 9-4935-282-34
803D
SECTION I
INTRODUCTION AND SPECIFICATIONS
1-1. INTRODUCTION
with a standard cell for the 803D and 803DR and with a Zener
reference diode for the 803D/AG and 803DR/AG. The known
a. This instruction manual is for use with the 803D series
adjustable reference voltage is provided by a 500 volt DC
AC/DC Differential Voltmeters. These are available in either a
power supply and five Kelvin-Varley decade resistor strings
cabinet model or a standard 19 inch rack model, and with
that are set accurately by five voltage readout dials. In this
either a standard cell or a Zener diode as the reference
way, the 500 volts can be precisely divided into increments as
element. Model designations are: 803D (cabinet model,
small as 10 microvolts. The unknown voltage is then simply
standard cell); 803DR rack model, standard cell); 803D/AG
read from the voltage dials. When used as an AC differential
(cabinet model, Zener diode); and 803DR/AG (rack model,
voltmeter, the 803D operates essentially the same as for DC
Zener diode).
differential measurements. The AC input voltage is converted
b. The high accuracy, portability, and compactness of
to a DC voltage and this DC voltage is measured by comparing
the 803D make this instrument ideal for the precise
it to a known adjustable reference voltage. In the highest
measurement of almost any AC or DC voltage.
Ease
recommended null sensitivity range, potential differences
operation, inherent protection from accidental overload, and
between the unknown and the reference voltage of only 0.001
high reliability contribute to the outstanding performance that
volts for DC and 0.001 volts for AC will cause full scale meter
assures suitability for both production line testing and precision
deflection.
laboratory measurements. This instrument is capable of being
d. The instrument is normally supplied ready for use on
used as a vacuum tube voltmeter, as a precision
115 volts. Upon request, instruments are supplied for 230
potentiometer, and as a megohmmeter for measurement of
volts operation. If it becomes desirable to convert from one
high resistance. It can also be used to measure the excursions
mode of operation to the other, refer to the instruction decal on
of a voltage about some nominal value. One feature that
the back of cabinet models or on the cover in rack models.
should be emphasized is that no current is drawn from the
unknown source for DC measurements when balance is
1-2. DAMAGE IN SHIPMENT
attained. Thus the determination of the unknown DC potential
is independent of its source resistance. The 803D is basically
Immediately upon receipt, thoroughly inspect for any damage
used for measurements of DC voltages from 0 to 500 volts and
that may have occurred in transit. If any damage is noted,
AC voltages from 0.001 to 500 volts. However, high accuracy
follow the instructions outlined on the warranty page at the
measurements to 30,000 volts DC are possible with precision
back of this manual.
voltage dividers especially designed for use with the Fluke
Model 800 Series Differential Voltmeters. As additional
1-3. SPECIFICATIONS
features, this instrument contains a polarity switch for equal
convenience in measuring positive or negative DC voltages
and an adjustable recorder output which makes the 803D
AS A PRECISION POTENTIOMETER
particularly useful for monitoring the stability of almost any AC
or DC voltage. Furthermore, the 803D meter has taut-band
DC ACCURACY:
suspension which eliminates problems due to meter stickiness.
c. When used as a DC differential voltmeter, the 803D
+0.02% of input voltage from 0.1 to 500 VDC
operates on the potentiometric principal. An unknown voltage
+(0.02% +25 uv) below 0.1 VDC
is measured by comparing it to a known adjustable reference
voltage with the aid of a null detector. An accurate standard
for measurements is obtained by setting the reference supply
1-1
