An analog electro-optical multiplier.
Loading...
Authors
Anderson, Thomas McArthur
Subjects
Advisors
Date of Issue
1963
Date
Publisher
Massachusetts Institute of Technology
Language
en_US
Abstract
An Analog Electro-Optical Multiplier, a simple and compact
buiid state device with no moving parts, has been designed,
constructed, and tested. Functionally, this device is the direct
analog of the familiar servo-multiplier, being capable of
multiplying one analog variable by up to seven other individual
analog variables. The servo-driven potentiometer arm has been
replaced by a photoconductive cell, illuminated by a low-power
lamp, connected in a bridge circuit with two fixed resistors. The
servomechanism driving the potentiometer arm has been
replaced by a solid state operational amplifier driving the lamp
in response to the value of the multiplicand. Accuracies of 0. 62 per cent of full scale have been obtained
with this multiplier which has a dynamic range of 4 cps. An
important advantage of this multiplier is the appreciable reduction
in the number of operational amplifiers required compared to
analog multipliers currently on the market, both for four quadrant
and two quadrant multiplication. Initial experiments were conducted using the Raytheon
Raysistor, an electro -optical device consisting of a light source
and a CdSe photoconductive cell. The effects of signal heating,
hysteresis, and signal voltage across these cells is discussed
and compared with the improved characteristics of the CdS
photocells which were used in the final design. The problem of uniformly illuminating several of these cells
with a single lamp is discussed. In addition, the properties of
miniature lamps with regard to light output, power requirements,
and speed of response is considered.
Type
Thesis
Description
Series/Report No
Department
Electrical Engineering