クルプカ，マイケル・エイ

Bio: クルプカ，マイケル・エイ is an academic researcher. The author has contributed to research in topics: Signal & Ground. The author has an hindex of 1, co-authored 1 publications receiving 5 citations.

Low-noise electric field sensor

Abstract: A system for measuring the free space electric field comprises an ultra high impedance of the antenna disposed in an electric field to generate a signal from the electric field. Amplifier having an input port is provided to amplify the signal. Amplifier generates an input bias current, the current is combined with the signal to produce an input potential at the input port. Connected to an electrical circuit ground connection to an input port, comprising at least one circuit element for controlling the input potential to stabilize the signal at the input port.

A Capacitive-Coupled Noncontact Probe for the Measurement of Conductivity of Liquids

Abstract: A noncontact (capacitive-coupled) probe for the measurement of the conductivity of liquids is presented. Insulation introduced between the measurement electrodes and the liquid intrudes a couple of coupling capacitances. Though the capacitive coupling overcomes the problems of electrode polarization and contamination associated with contacting electrodes, the large reactances of the coupling capacitors pose a problem in the measurement of comparatively very small resistance of the liquid. An auto-balancing signal conditioning scheme presented here overcomes the problem posed by the large capacitive reactances and provides directly a measurable output proportional only to the conductance of the liquid. Error analysis of the probe presented herein helps the optimal design of the probe. A worst case error of ± 0.9% was obtained from a prototype noncontact conductivity probe, developed and tested.

Noncontact ECG system for unobtrusive long-term monitoring

Abstract: This paper describes measurements made using an ECG system with QUASAR's capacitive bioelectrodes integrated into a pad system that is placed over a chair. QUASAR's capacitive bioelectrode has the property of measuring bioelectric potentials at a small separation from the body. This enables the measurement of ECG signals through fabric, without the removal of clothing or preparation of skin. The ECG was measured through the subject's clothing while the subject sat in the chair without any supporting action from the subject. The ECG pad system is an example of a high compliance system that places minimal requirements upon the subject and, consequently, can be used to generate a long-term record from ECG segments collected on a daily basis, providing valuable information on long-term trends in cardiac health.

An auto-balancing signal conditioning scheme for non-contact measurement of conductivity of water

Abstract: This paper presents a signal conditioning approach to measure resistance and hence conductivity of water in an insulating tube through capacitively coupled electrodes. In the scheme presented, the electrodes are electrically insulated from water and measurement is taken through couple of capacitances formed between the electrode and water column. The capacitive coupling overcomes the problems of electrode polarization and contamination associated with conventional contact based approach of conductivity measurement of water. The large reactance of the coupling capacitors, compared to the resistance of the water column under measurement, is a challenge. Moreover, the variations in the coupling capacitor over time presents another challenge. The auto-balancing signal conditioning scheme presented here overcome these challenges by providing an output that is directly proportional to the resistance under measurement and is independent of the value of the coupling capacitors. Test results on a prototype of the proposed circuit show that the maximum error in the resistance measurement is less than 0.9 % and the output is independent of the coupling capacitors.

A Capacitance-to-Digital Converter with Sinusoidal Excitation Suitable for Series RC Sensors

Abstract: A new Capacitance-to-Digital Converter (CDC) applicable for series RC sensors that requires/prefers sinusoidal excitation is proposed in this paper. The CDC presented works based on a dual-slope technique and it gives a digital output as a function of unknown capacitance of a series RC sensor, i.e., a capacitive sensor with a capacitor and a resistor in series in its electrical equivalent circuit. Output of the CDC is not sensitive to the series resistor. The CDC is useful for grounded as well as floating capacitive sensors, which needs to be excited with a sine wave for best performance. Applications of such capacitive sensors include ice detection, sterility testing of packed food products, etc. A sinusoidal Howland current source can be used to excite a grounded capacitive sensor while a simple current source with a special stabilization scheme that suppresses the effect due to static errors of opamp has been developed for floating capacitive sensor and presented in this paper. A prototype of the proposed CDC for a floating capacitive sensor has been built and tested in the laboratory. Measurement results for the sensor capacitance showed a worst case error of 0.13% for a range of 100 pF, proving the efficacy of the proposed scheme. Keywords-Capacitance-to-digital converter; capacitive sensor; floating capacitive sensor; current source for capacitive sensors.

Ultra high impedance voltmeter for electrostatic applications

Abstract: A new kind of voltmeter suitable for electrostatic measurements is proposed. It features an extremely high input impedance (more than 3/spl middot/10/sup 16/ /spl Omega/) and very low input capacitance (less than 10/sup -16/ F). Such low input capacitance and high input resistance allow for contacting voltage measurements which transfers virtually no electric charge to/from the measured object. The voltmeter combines a voltage follower technique with a unique input zeroing and bias current cancellation circuit. It has been designed specifically for monitoring the voltage on electrostatic sensitive devices during their handling and processing.