| 摘要 |
1,116,449. Measuring temperature electrically. UNITED SYSTEMS CORPORATION. Nov. 12, 1965 [Nov. 16, 1964], No. 48160/65. Heading G1N. Apparatus for measuring temperature comprises a negative temperature coefficient thermistor 13 in a self balancing D.C. bridge circuit having a digital display 22. Potentiometer 16 is a linear potentiometer with a function shaping network consisting of resistors (41, 42, 43), Fig. 2 (not shown) connected across tapped portions of the potentiometer to match its output to the characteristic of thermistor 13. Resistor 12 is chosen to have a resistance which is midway between the extreme resistances of the thermistor. In Fig. 2 (not shown), four jacks for connection to four thermistor probes and also a calibration resistor or decade resistance box (70) may be selected by a switch (31). Dummy resistors (80, 81, 82, 83) are substituted in the absence of probes to protect the bridge circuit. A second potentiometer (not shown), which is linear, may be driven by the gear train 23 to provide an analogue signal for control or recording. |
