| 摘要 |
The tocodynamometer has a detector which includes a pressure responsive button (2). Linear displacements of the button are converted into electrical signals by variation of inductance in a linear variable differential transducer (20). The button is typically centrally placed within a fixed pressure insensitive annular guard body (1). A leaf spring (4) resists displacement of the button and is calibrated such that under maximum load, deflection outside the linear range of the transducer does not occur. Preferred circuit arrangements include an oscillator detector (22) which supplies the transducer (20) with its exciting voltage and also detects output from the transducer (2). Output from the detector is applied to a differential amplifier whose output is coupled to a receiver demodulator. The output from the receiver demodulator is coupled to a chart recorder or other display means. The circuit also includes power supply circuit and a zero setting for the differential amplifier. |
