Abstract: A solid state temperature compensated annunciator is disclosed. The solid state temperature compensated annunciator includes a pressure sensor for measuring a pressure of the fillant within a vessel and a temperature sensor for measuring the temperature of the fillant within the vessel. The solid state temperature compensated annunciator determines a pressure that the vessel would have if the vessel were filled with a predetermined amount of fillant, and compares the measured pressure to the determined pressure. If the measured pressure is below the determined pressure, a warning signal is issued.

Abstract: An electro-optical counter or detecting apparatus for detecting passage of items therepast. A light emitter projects a constantly pulsed beam of light onto the path of the items and light sensors sense the optical energy reflected from such items. One sensor controls the light emitter to so regulate the amount of light emitted by each pulse that the amount of optical energy reflected by the items does not vary as a function of the reflectivity of the surfaces of such items and does not exceed a predetermined level. Another light sensor senses changes in optical energy beyond such predetermined level and thus senses only the passage of an edge of each item past the pulses light beam.