TB 9-4931-290-50
IDENTIFICATION AND DESCRIPTION
This bulletin provides instructions for the
calibration of Voltage Calibrator, Ballantine Model 421A. The manufacturer's manual was
used as the prime data source in compiling these instructions. The equipment being
calibrated will be referred to as the TI (test instrument) throughout this bulletin.
a. Model Variations. None.
b. Time and Technique. The time required for this calibration is approximately 2
hours, using the dc and low frequency technique.
prescribed by TB 750-25.
b. Adjustments to be reported are designated (R) at the end of the sentence in which
they appear. When adjustments are in tables, the (R) follows the designated adjustment.
Report only those adjustments made and designated with (R).
pertain to this calibration are listed in table 1.
Test instrument parameters
Performance specifications
Dc volts
Range: 0 to 111 V
Accuracy: (0.2% setting +0.007% range +25 V)
Ac volts
Range: 0 to 111 V at 1 kHz
Accuracy: (0.15% setting +0.005% range +3 V)
Range: 0 to 100 V at 400 Hz
Accuracy: (0.25% setting +0.005% range +3 V)
Range: 100 to 1000 V at 400 Hz
Accuracy: (0.45% setting +0.005% range +3 V)
Stability
Range: 105 to 125 V
Accuracy: 0.09%
Range: 400 Hz or 1 kHz
Accuracy: 3%
Distortion
Less than 0.2%
EQUIPMENT REQUIREMENTS
calibration procedure. This equipment is issued with Secondary Transfer Calibration
Standards Sets AN/GSM-286; AN/GSM-287; or AN/GSM-705. Alternate items may be used
by the calibrating activity. The items selected must be verified to perform satisfactorily
prior to use and must bear evidence of current calibration. The equipment must meet or
