A self adjusting power supply for induction charging electrodes used in electrostatic spray coating apparatus is disclosed. A first resistance of high ohmic value is connected in series between a source of high direct current voltage and the induction charging electrode, while a second resistance is connected between the source of voltage and a ground reference point. The first resistance acts as a voltage divider with the spacial impedance which exists between the charging electrodes and ground in the spray nozzle of the spray coating apparatus, and serves to regulate the charging voltage and to compensate for variations in the conductivity of the material being sprayed. If the value of the spacial impedance should decrease for any reason, the increased current flow therethrough produces an increase in the voltage drop across the first resistance, thereby reducing and thus regulating the potential at the charging electrodes and serving to prevent corona and arcing within the spray gun. The ohmic value of the first resistance, which is in the range of 1-50 gigohms, is sufficiently high to prevent any substantial current flow from the charging electrode, thereby reducing the shock hazard of the spray gun, and also to prevent any significant changes in the current flow due to changes in the conductivity of the spray material. The second resistance serves as a bleeder for the charges on the spray gun and the induction charging electrode when the gun is turned off.
A method and apparatus for creating electrostatic field by forming a high resistive anodic-oxidized film on an electrostatic electrode and applying thereto a high voltage direct current including high frequency component resonatable with inherent resistance and capacitance in the high resistive film.
A hand held electrostatic powdered paint spray gun that has a trigger which allows the user to vary the voltage and the paint density supplied to the gun. The trigger is coupled to a potentiometer that provides an output voltage to circuits that control the flowrate of the paint powder and a voltage supply to the paint powder.
A compact and modularly designed apparatus for testing and burning-in semiconductor devices comprises first and second power supplies and the use of direct current (DC) to DC converters. The first power supply provides a high voltage low amperage power source to drive the devices under test (DUTs), and the second power supply supplies 15 volts and 5 volts to drive the circuitry on the testing equipment. The high voltage and low amperage is supplied to slot boards, and the DC to DC converters alter the voltage and current to digital levels. Supplying high voltage and low amperage power through the system to a location electrically near the DUTs, then converting it with DC to DC converters to power the DUTs, allows for much smaller connectors and for a modularly designed burn-in oven.
A plurality of stages of capacitors and diodes interconnected in a parallel wired Cockcroft-Walton multiplier circuit, wherein capacitors in successive stages of the circuit are constructed of reduced physical size as compared with preceding stages, corresponding to reduced capacitor voltage ratings, to provide a cascade multiplier circuit of reduced total length.
A compact and modularly designed apparatus for testing and burning-in semiconductor devices comprises first and second power supplies and the use of direct current (DC) to DC converters. The first power supply provides a high voltage low amperage power source to drive the devices under test (DUTs), and the second power supply supplies 15 volts and 5 volts to drive the circuitry on the testing equipment. The high voltage and low amperage is supplied to slot boards, and the DC to DC converters alter the voltage and current to digital levels. Supplying high voltage and low amperage power through the system to a location electrically near the DUTs, then converting it with DC to DC converters to power the DUTs, allows for much smaller connectors and for a modularly designed burn-in oven.
