| 摘要 |
<p>1,255,631. Measuring electrically. SHIHYING LEE and YAO TZU LI. Nov. 8, 1968 [Nov.8, 1967], No.50988/68. Headings G1N and G1U. A transducer system includes sensing networks 11, 13 including impedance elements, e.g. capacitors C 1 , C 2 or resistors R 1 , R 2 , variable in response to pressure, acceleration or temperature, a D.C. source having high and low voltage output levels E h , E 1 , switches 3, 4, connected to input terminals of the sensing networks whereby the output voltages e 01 , e 02 of the networks are caused to vary in alternation between the voltages E h , E 1 at a rate dependent on the parameter to be measured, a switch 5 controlling the switching of the input terminals of the two networks when a respective output voltage reaches a reference level E r , whereby the mean voltage difference e OUT between the input voltages to the sensing networks is proportional to the parameter to be measured. An alternative embodiment, Fig. 5 (not shown) utilizes a multi-vibrator as the switching means. A complete circuit for a third embodiment is given in Fig.8 (not shown). Figs.3, 4 illustrate displacement-responsive differential capacitors suitable for use in the sensing networks. The thermal co-efficients of the sensing elements are chosen to be mutually compensatory for ambient temperature changes.</p> |
