Thermal measuring and testing – Temperature measurement – By electrical or magnetic heat sensor
Patent
1986-12-30
1988-11-08
Cuchlinski, Jr., William A.
Thermal measuring and testing
Temperature measurement
By electrical or magnetic heat sensor
374163, 128736, G01K 700
Patent
active
047831758
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a temperature measuring apparatus devised so as to display measured temperatures selectively in two kinds of temperature scale, namely in degrees centigrade and in degrees Fahrenheit.
BACKGROUND OF THE INVENTION
The most commonly used temperature scales are the centigrade scale and the Fahrenheit scale. Both of the two scales are used in some countries, while either of the two is used in some other countries. Such being the case, temperature measuring apparatus are desired, as the case may be, to have a function of displaying measured temperatures selectively in both the two scales.
A Fahrenheit temperature value t.sub.F (.degree.F.) is related to a centigrade temperature value t.sub.C (.degree.C.) through an equation: ##EQU1## which shows that the freezing point 0.degree. C. and boiling point 100.degree. C. of water under a pressure of 1 atmosphere correspond to 32.degree. F. and 212.degree. F., respectively.
In a temperature measuring apparatus devised so as to analog-display on an analog meter a temperature measured, for instance, by making use of the temperature-dependent characteristic of a semiconductor device such as a transistor, the measured temperature can easily be read out in both the centigrade and the Fahrenheit scales by graduating the analog meter in both the centigrade and the Fahrenheit scales. However, in case of digitally displaying the measured temperatures, the apparatus not only necessiates, on the assumption that a temperature sensor used therein outputs a signal in proportion to a centigrade temperature value, an A-D converting means for digitally displaying the centigrade temperature value itself, but also needs, for a digital display of a corresponding Fahrenheit temperature value, either a means for digitalizing through A-D conversion a signal which is made proportional to a corresponding Fahrenheit temperature value in advance by performing an analog arithmetic operation on the output from the temperature sensor in accordance with Eq. (1), or a means for performing, in accordance Eq. (1), a digital arithmetic operation on a signal quantized in advance by A-D converting the output from the temperature sensor. The present invention employs the former system in which an analog arithmetic operation on the sensor output is followed by an A-D conversion. Relating to the system a prior art is described in the following on reference to FIG. 4:
In the figure, a temperature sensing circuit 2, which uses a transistor 1 as a temperature sensor, outputs on an output terminal 3 a voltage e.sub.C =kt.sub.C which is proportional to a centigrade temperature t.sub.C. An A-D converter 5, which has input terminals REF.sup.+ and IN.sup.+ for receiving respectively a reference voltage e.sub.r and signal voltage e.sub.s, outputs a digital signal proportional to e.sub.s /e.sub.r, the ratio of the signal voltage e.sub.s to the reference voltage e.sub.r. The ratio e.sub.s /e.sub.r is displayed by a display unit 6. The A-D converter 5 is supplied at its reference voltage input terminal REF.sup.+ with the reference voltage e.sub.r obtained by dividing with the resistor 7 a stabilized positive voltage E.sub.a being supplied from a terminal 8. Further, resistors 10, 11, 12 and an operational amplifier 13 constitute an analog arithmetic operation circuit, which derives according to Eq. (1) a voltage e.sub.F proportional to a Fahrenheit temperature t.sub.F from a voltage e.sub.C (=kt.sub.C) outputted to the terminal 3 in proportion to the centigrade temperature t.sub.C. Either of the two voltages e.sub.C and e.sub.F is selectively inputted to the A-D converter 5 through a switch 4.
In such a circuit constitution as described above, the voltage e.sub.C =kt.sub.C proportional to the centigrade temperature is inputted to the input terminal IN.sup.+ of the A-D converter 5 with the switch 4 turned to a contact a. On the other hand, the reference voltage e.sub.r supplied to the reference voltage input terminal REF.sup.+ of the A-D converter rom the voltage
REFERENCES:
patent: 4068526 (1978-01-01), Goldstein
patent: 4121462 (1978-10-01), Mohrman
patent: 4198676 (1980-04-01), Varnum et al.
patent: 4206649 (1980-06-01), Nagaie
patent: 4277975 (1981-07-01), Pinkham
patent: 4321933 (1982-03-01), Baessler
patent: 4423968 (1984-01-01), Nemcek, Sr. et al.
patent: 4464067 (1984-08-01), Hanaoka
patent: 4497586 (1985-02-01), Nelson
patent: 4636092 (1987-01-01), Heayi
Cuchlinski Jr. William A.
Will Thomas B.
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