Permanent Digital Function Storage using Neon Tubes

For some purposes, such as storage of tables needed in computations, an electronic memory unit which does not have the capability of changing its contents may be used. The required information may therefore be permanently wired in at the time of construction or be changed only by manual operations. A memory of this type utilizing the presence or absence of a small neon tube as the memory element is presented here. The layout of the memory is in effect rows and columns of wires with the neon tubes connected at the appropriate intersections. The neon tube detects a ``coincident voltage´´ at the intersection and the resultant light output is converted back to voltage by means of a photo tube.