Thermostat Schematic

Brief description of the digital thermostat

Brief description of the digital thermostat

FIG. 1 is a perspective view of a digital thermostat control which incorporates the invention;

FIG. 2 is a block diagram which illustrates a conventional Wiring arrangement for a home heating system;

FIG. 3 is a simplified block diagram of the digital thermostat control shown in FIG. 1;

FIG. 4 illustrates a power dividing circuit which energizes the digital thermostat control of FIG. 1 by power derived from the existing heating relay circuit of FIG. 3;

FIGS. 5A and 5B are simplified block diagrams of an integrated circuit which implements the logic and counting functions for carrying out the objects of the invention;

FIGS. 6A and 6B are waveforms which graphically illustrate operation of the power divider circuit of the invention;

FIGS. 7A, 7B and 7C are waveforms which represent three operating modes of the digital thermostat shown in FIG. 1;

FIG. 8 is a block diagram which identifies the timing signals which are developed by the clock shown in FIG. 5B;

FIG. 9 illustrates the alternation of time scan and temperature scan intervals with display intervals;

FIG. 10 is an elevation view, partly in section, of a portion of a slide switch shown in the room thermostat of FIG. 1;

FIG. 11 is a view of the slide switch of FIG. 3 taken along the line XI–XI of FIG. IV;

FIG. 12 is a wiring diagram of a protective switching circuit for coupling the digital thermostat of the modulating valves

to the existing wiring of a home heating and air conditioning system which features first and second stage heating modes and a cooling mode of operation;

FIG. 13 is a combination block diagram and Circuit Diagram which illustrates the principal external connections for a control module equipped for dual cycle operation;

FIGS. 14A and 14B are waveforms applied to energize an element of a liquid crystal display;

FIG. 15 is a Schematic Diagram of a day skipper circuit; and,

FIGS. 16A, 16B, 16C and 16D comprise a set of waveforms useful in understanding the operation of the day skipper circuit shown in FIG. 15.

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digital thermostat modulating valves

Temperature Sensor using Thermistor