Front Cover

Dory Launching, circa 195

Trielectrode capacitive pressure transducer

A capacitive transducer and circuit especially suited for making measurements in a high-temperature environment are described. The transducer includes two capacitive electrodes and a shield electrode. As the temperature of the transducer rises, the resistance of the insulation between the capacitive electrode decreases and a resistive current attempts to interfere with the capacitive current between the capacitive electrodes. The shield electrode and the circuit coupled there reduce the resistive current in the transducer. A bridge-type circuit coupled to the transducer ignores the resistive current and measures only the capacitive current flowing between the capacitive electrodes

Vibrating-membrane electrometer has high conversion gain

Vibrating-membrane transducer in a circuit can measure current below 10 to-the-minus 17 ampere. This electrometer has a high conversion gain and a minimum internal power consumption

Vibrating element electrometer with output signal magnified over input signal by a function of the mechanical Q of the vibrating element Patent

Vibrating element electrometer producing high conversion gain by input current control of elements resonant frequency displacement amplitud