Temperature sensor employing married diode junction means

Claim 1

In a system employing a plurality of temperature sensors, the improvement comprising: a. a diode junction temperature sensor for measuring the temperature; said diode junction temperature sensor including a plurality of diode junctions that are serially connected, each diode junction having an operating curve that is different from a predetermined standard operating curve; said diode junctions being pre-selected to have a summation of their respective departures from said predetermined standard operating curve substantially zero whereby said diode junction temperature sensor has a predetermined voltage drop at a predetermined temperature and a predetermined constant current flow therethrough and has a substantially linearly varying voltage drop at said predetermined constant current within the range of -50* F. to +250* F. for the requisite economy, linearity and interchangeability; b. power supply means and regulator means for maintaining a substantially constant current flowing through said diode junction temperature sensor; said power supply means and said regulator means being serially connected with said diode junction temperature sensor in the forward biased direction; said diode junction temperature sensor being serially connected to electrical common; and c. a readout lead connected with the juncture of said diode junction temperature sensor and said regulator means such that voltage is measured with respect to said electrical common to form a signal that is a function of the sensed temperature; said voltage being sensed with no substantial current flow on the readout lead so as to be insensitive to the length of said readout lead; said readout lead being adapted to be connected into readout means for monitoring the sensed temperature such that any temperature sensor in said system may be replaced without recalibration and without introducing significant error into the system.