TB 9-5985-313-40
Figure 2. Output calibration factor - equipment setup.
8. Output Calibration Factor
NOTE
When Hewlett-Packard Model 478A thermistor mounts with
Options H55 and H75 are used, difficulties are encountered in
obtaining a null due to bolometer bridge oscillations. A
capacitor with a value between .01 and 0.09 PF should be
connected between terminals 7 and 10 of the power bridge.
The oscillations can be observed by connecting oscilloscope to
the same point.