Abstract: Apparatus for measuring corona current in high voltage A.C. ionizers uses an electrical sensor adjacently spaced from at least one of the discharge electrodes and coupled to electronic circuitry for separating capacitive current from the corona current. In one mode, the capacitive current component is measured directly by a first sensor adjacently spaced from one discharge electrode whose corona current flow to such electrode is either obstructed or squelched entirely while a second sensor monitors total current. The signals from the two sensors are electrically subtracted when applied to opposing inputs of a differential amplifier to provide an output signal proportional to just corona current. In a second mode, a measure of corona current is again provided by electrically subtracting from a total current signal input to a differential amplifier a signal equal to the capacitive current component.

Abstract: A method and apparatus for determining ion flow imbalance. High-magnitude positive and negative potential sources, each having a high-magnitude potential output terminal, are provided. Two electrodes are adapted for positioning adjacent the location of ions, the electrodes having areas for exposure to the ions. A supply of operating potential is provided for the high-magnitude potential sources. The operating potential supply is switched to supply operating potential alternately between the high-magnitude potential sources. Neutral terminals are provided on each of the high-magnitude potential sources and the current flows from the neutral terminals of the high-magnitude potential sources to reference potential are sensed to determine the current flows to the electrodes.

Abstract: An instrument for non-contact measurement of electrostatic fields and related parameters, such as electrostatic potential, voltage and charge density of a charged object, includes a sensor for sensing the electrostatic field produced by the object and for producing an electrical signal, a display for producing a visual readout related to the electrical signal and a range scaling circuit for coupling the sensor to the display. The range scaling circuit is coupled to logic which switches the range scaling circuit and the display back and forth between two ranges, one for relatively higher strength field measurements and one for relatively lower strength field measurements. Because the distance at which the instrument is held from the charged object to achieve an accurate reading depends upon the strength of the field, the range scaling circuit is also coupled to circuitry which indicates the appropriate distance from the charged object at which the instrument must be held to provide an accurate measurement.

Abstract: Ionizing gas gun for ultra-clean static neutralization comprises a plastic nozzle enclosing positive and negative ion discharge electrodes and means for blowing a gas, such as air or nitrogen therethrough. A trigger actuates both the release of gas and application of positive and negative high voltage to the respective discharge electrodes, including delay circuitry for suspending discontinuance of the positive high voltage to its electrode for a momentary period subsequent to discontinuance of the negative high voltage when the gas is cut off in compensation of a slight preponderance of negative ion emission otherwise effected at cut-off. Venturi ports at the nozzle tip draw air over the discharge electrodes for admixing with higher mobility nitrogen ions when nitrogen rather than air is employed as the blowing medium. A changeable filter insures cleanliness, including monitoring means to indicate clogged or ruptured filter conditions or improper installation.

Abstract: A transmitting system including an admittance sensing probe having sensing elements adapted to sense both the composition and the level of materials. The probe is coupled to admittance responsive networks forming part of a common oscillator which generate admittance signals representing the level and composition of the material. A remotely located power supply provides current to the transmitters through two pairs of lines, and the output currents of the transmitters represent the level and composition of the materials.