Potentiometer for measurement of small photoelectric currents

A survey of the equipment and procedures for the photometry of projectors at the National Bureau of Standards

“…The Photometer Bar of the 30-Meter Range The Goniometer of the 30-Meter Range The Goniometer of the 279-Meter Range Figure 6 The Arrangement of the Photometric Equipment on the 279-Meter Range The object of this report is to describe the procedures used and equipment available for projection photometry at the National Bureau of Standards, This paper besides serving as a guide for making this type of measurements, will make a de» tailed description of the procedures for photometric measurement of projectors unnecessary in future NBS test reports.…”

“…. 6 Figure 7 13are color-corrected by means of optical 'f liters ir order to make their response similar to the CIE spectral luminous efficiency function. Two different types of photosens it or s are in general use, the barrier-layer photocell and the vacuum phototube.…”

Emergency vehicle warning devices:

“…The model purchased can be expanded to a full fourteen channels with the addition of the record/reproduce electronics for the additional channels and a modification of the heads and hub to accomodate the one-inch tape (7 channel recording utilizes 1/2 inch tape). 48 The wide bandwidth range results from a feature which allows the selectability of three different modes of operation: The present unit has six channels of F.M. record electronics and one channel of direct record electronics.…”