A 4 Π Light Meter1

A Simple, Sensitive Underwater Photometer1

“…The availability of inexpensive, yet highly sensitive photoconductive cells has led to applications for measuring natural light (Maddux 1966;Wiens 1967;Berry and Raney 1968). Several circuits involving series resistance or the Wheatstone principle have been used for the purpose of linearly transposing incident light from resistance change in the photocell to deflection of an ammeter.…”

“…The voltage-splitter principle is used, where a given voltage is tapped from a resistor in series with a power source. This design was used in a simple form by Maddux ( 1966)) but our circuit uses several adjustable steps rather than a potentiometer.…”

A simple and inexpensive 4π light collector and two designs for a light meter for light attenuation studies

“…In the case of phytoplankton a spherieal or 4TT detector has the most appropriate geometry for such measurements, A variety of designs for 4-17 detectors may be found in the literature (Atkins & Pool. 1940;Curric, 1960: Tyler, 1961Maddux, 1966;Smith & Wilson, 1972;Booth, 197f>;Htijerslev, 1975). Some of the designs would present diffieulties to a laboratory with modest machine shop facilities; in addition, few of the published designs provide adequate construction details.…”

The design and evaluation of a measurement system for photosynthetically active quantum scalar irradiance1

“…Several described instruments could measure scalar irradiance (e.g. Tyler 1955;Austin 1959;Maddux 1966;Rich and Wetzel 1969;Sasaki et al 1966;Currie 1960). For various reasons the spectral responses of these devices are unsuitable for the measurement of light in photosynthetic research.…”