Abstract: A temperature-controlled thermoelectric cooling system regulates the flow of electric current into the thermoelectric cooler in order to maintain a desired cold-side temperature without directly measuring the temperature of the device affixed to the cold side of the cooler. The system includes an apparatus for periodically interrupting the current flowing to the cooler, and during these interruptions measuring the open circuit voltage across the cooler induced by the temperature difference between the hot and cold sides. Computational means use this voltage measurement in conjunction with the temperature of the hot side of the cooler to determine the cold side temperature. From the cold side temperature determination, a controller regulates the current flow to the cooler to maintain a desired cold side temperature.

Abstract: An electro-optical display in a programmable electronic thermostat includes a plurality of selectively energized display elements which cooperate with a 24-hour time indicia to provide a continuous visual display of the time periods during which a specific programmed space temperature is to be maintained.