| 摘要 |
A silicon junction diode is used as one element of a resistance bridge to form the temperature sensing element of an electronic thermostat. Current through the diode is maintained at approximately constant value so that the negative temperature coefficient characteristic of the diode can be utilized. The values of the fixed resistors in the bridge are selected so as to provide a null at a preselected temperature. Used in conjunction with a voltage comparator circuit having positive feedback, a digital control signal is provided whenever the temperature of the sensing element rises above the preselected null value. The addition of a single NOR gate allows the combination of this digital control signal with an external control signal.
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