MM0474
CAUTION
For AC operation, set the rear-panel 115V-230V switch to
the proper position before connecting the power cord to
the service outlet.
2.
GENERAL.
a. This section presents the basic information required to operate the
Model 8402B Calibrator.
b. The 8402B is an accurate source of DC power.
DC power output is
continuously variable or can be set to 431C full-scale range levels with front
panel controls. Variable output current control permits DC substitution power
measurement with the 431C, from 1 W to 10 mW. These power levels are used to
check calibration accuracy of the 431C. In addition, power levels of 8.0, 6.0,
4.0, and 2.0 mW can be selected to check power meter tracking accuracy.
c. The operating resistance of the RF detection thermistor element used on
a 431C power measurement can be accurately determined using the 8402B.
The
front panel RESISTANCE STANDARD jack connects precision resistance circuits to
the RF detection bridge in the 431C Power Meter. By rotating the front panel
switch, the meter on the 431C is used to indicate the position of the switch at
which normal operation circuit conditions exist.
Thermistor mount resistance
error is determined using the MOUNT RESISTANCE switch.
3.
CONTROLS, CONNECTORS, AND INDICATORS.
The front and rear panel controls, connectors, and indicators are explained
in Figure 2. The descriptions are keyed to the corresponding items which are
indicated on the figure.
Further information regarding the various settings
and uses of the controls, connectors, and indicators is included in the
following paragraphs of this lesson.
4.
OPERATING INFORMATION.
Refer to Figure 3 for step-by-step instructions for operating the 8402B. A
procedure for measuring the operating resistance of the RF detection thermistor
element is included as part of the DC substitution procedure. Instructions for
using the 8402B to check 431C calibration and meter tracking accuracy are given
in Paragraph 6.
5.
DC SUBSTITUTION.
a. Power meter instrumentation error can be reduced by
using
DC
substitution. With precision instruments used in a DC substitution
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