Abstract: A Style B PAPI system comprises a plurality of identical lamp housing assemblies, each with one or more lamps and each housing assembly including: an electronic bypass circuit with first and second oppositely poled SCRs coupled across the terminals of each lamp; a zener diode; and a diode bridge for developing a first trigger voltage across the zener diode in the event of failure of a lamp. The first trigger voltage causes alternate conduction in the first and second SCRs from the AC voltage developed across the failed lamp. A lamp control circuit includes a third SCR that is coupled across the zener diode for developing a second trigger voltage for similarly driving the SCRs. The lamp control circuit is operated by a microcontroller-controlled common lamp control circuit that activates all of the lamp control circuits and disable all of the lamps in response to a tilt condition for the lamp housing assembly.

Abstract: The air caloric stimulation system provides an adjustable air system with accurate and automatic control of the delivery and temperature of air. A thermal electric device utilizing the Peltier effect generates or absorbs heat depending on the difference between the temperature of the air at the outlet and the "set" or desired temperature of the air at the outlet. Further, the Peltier units are aided in controlling the temperature of the air using a radiator system in conjunction with a liquid circulating system. The current to the Peltier units are controlled using unique proportional phase controlled signals. Safety circuitry prevents the air or liquid from overheating.