Linear telethermometer

Claim 2

A nearly linear telethermometer device comprising a remote thermistor connected in series with one or more semiconductor diodes of any composition with a voltage-current relationship given by i = I.sub.o (e.sup. v/n.sup.λv.sbsp.o -1) where n is the number of diodes and being either discrete or integrated circuit devices, means for electrically connecting a biasing potential to said thermistor and diode(s) such that the diodes are forward biased, means for electrically connecting across said diode(s) device for measuring the voltage produced across said diode(s) which varies according to changes in the temperature of said thermistor.

Claim 3

A nearly linear telethermometer device comprising a remote thermistor connected in series with one or more (e diodes of any composition with a voltage-current relationship given by i = I.sub.o (e.sup.v/n.sup.λv.sbsp.o -1) where i is the current through said diodes, I o is the reverse saturation current of said diodes, v is the output voltage, n is the number of diodes, and 2v o is the diode thermal voltage, said diodes being either discrete or integrated circuit devices, resistance whose value is selected to be that of said thermistor at any desired reference temperature with said resistance connected in series with the same number of identical diodes as are connected in series with said thermistor, wherein said reference resistance and associated diodes are electrically connected in parallel with said thermistor and associated diodes, thereby forming a bridge circuit, means for connecting biasing potential to aforedescribed circuitry such that all diodes are forward biased, means for electrically connecting a device between the junction common to said thermistor and associated diodes and the junction common to said reference resistance and associated diodes for measuring the voltage produced by the aforedescribed bridge circuitry which varies according to the temperature of the said thermistor.

Claim 4

A nearly linear telethermometer device comprising a remote thermistor connected in series with one or more (e diodes of any composition with a voltage-current relationship given by i = I.sub.o (e.sup.v/n.sup.λv.sbsp.o -1) where i is the current through said diodes, I o is the reverse saturation current of said diodes, v is the output voltage, n is the number of diodes, and 2v o is the diode thermal voltage, said diodes being either discrete or integrated circuit devices, resistance whose value is selected to be that of said thermistor at any desired reference temperature with said resistance connected in series with the same number of identical diodes as are connected in series with said thermistor, wherein said reference resistance and associated diodes are electrically connected in parallel with said thermistor and associated diodes, thereby forming a bridge circuit, means for connecting biasing potential to aforedescribed circuitry such that all diodes are forward biased, means for electrically connecting a device between the junction common to said thermistor and associated diodes and the junction common to said reference resistance and associated diodes for measuring the voltage produced by the aforedescribed bridge circuitry which varies according to the temperature of the said thermistor.

Claim 5

The nearly linear telethermometer device as described in claim 2, wherein increased linearity is obtained by means of thermal feedback to said reference resistance by making a portion of said reference resistance thermally sensitive with a positive temperature coefficient and placing that portion in proximity with the said thermistor.

Claim 6

The linear telethermometer device as described in claim 2 wherein the output voltage of the bridge is taken across an output resistance with a positive temperature coefficient of the form R.sub.b = R.sub.1 + R.sub.t.sbsb.a.sbsb.o (1 + β(T.sub.a - T.sub.ao)) where R b is the value of said output resistance, R 1 is a fixed resistance, T a is the ambient temperature, T ao is a reference ambient temperature, and β is a constant of the material from which said wire is formed, in order to develop an output current and related output voltage which are independent of the ambiant temperature sensitivity of the semiconductor diodes.

Claim 7

The linear telethermometer as described in claim 2, wherein a portion of the output resistance is a current meter whose effective meter reading resistance contains the positive temperature coefficient.

Claim 8

The nearly linear telethermometer device as described in claim 2, wherein increased linearity is obtained by means of voltage feedback to said reference resistance by making a portion of said reference resistance voltage sensitive whereby that portion is regulated by a control circuit whose input is the voltage developed across those diodes which are connected in series with the said thermistor and whose output is such that the voltage sensitive resistance increases as the measured temperature increases.