Abstract:
A standard tungsten filament lamp of known color temperature, operating at its standard filament voltage, is successively viewed by a photometer device comprising a series of radiation sensors, each responsive to a different segment of the spectral output of the lamp and shunted by a variable resistor, with the series connected to a display device capable of simultaneously displaying a series of time-sequential voltage signals. The variable resistors are adjusted for equal output, or straight line response, on the screen of the display device. Then, a tungsten filament lamp of unknown color temperature is substituted for the standard lamp, without changing the resistor adjustments, and the filament voltage of the lamp is adjusted to produce another straight line response on the display device screen, not necessarily at the same amplitude as for the standard lamp. Under these conditions the unknown lamp is operating at the same color temperature as the standard lamp.
Abstract:
A phototransducer has a silicon photovoltaic cell corrected with two glass filters to the standard ICI spectral response equivalent to the spectral response of the human eye. Also, a method for correcting variations in the manufacture of the glass filters to adjust the filter to the thickness required for ICI correction of the silicon photocell.