Abstract: The invention is embodied in a method of determining an optimum de-chucking voltage for nullifying residual electrostatic forces on a wafer in an electrostatic chuck for removal of the wafer from the chuck, including holding the wafer on the electrostatic chuck by applying an electrostatic potential to the chuck, introducing a gas between the wafer and the chuck, reducing the electrostatic potential of the chuck while observing a rate of leakage of the gas from between the wafer and the chuck, and recording as the optimum dechucking voltage the value of the electrostatic potential obtaining when the rate of leakage exceeds a predetermined threshold.

Abstract: A circuit is provided for detecting a short circuit in a remote low-side driven load wherein a single conductor is used to both transmit a control signal from a microprocessor controller through a local driver to the remote driver of the load and also to transmit fault signals from the remotely driven load back to the control means. A control signal is transmitted from the microprocessor controller through a local driver circuit to a remote driver circuit on a single conductor. A short circuit at the remote load causes a fault signal to be latched for later detection by the microprocessor and a short circuit at the local driver is immediately detected.

Abstract: Solenoid control circuitry can be used with either a first solenoid requiring a relatively large holding current or a second solenoid requiring a relatively small holding current. A solenoid connected with the solenoid control circuitry is initially energized to effect operation of the solenoid from an unactuated condition to an actuated condition. A detector detects whether a characteristic of the initial energization of the solenoid corresponds to a characteristic of the first solenoid or the second solenoid. The solenoid control circuitry varies the amount of holding current supplied to the solenoid as a function of whether the detector detects the first solenoid requiring the relatively large holding current or the second solenoid requiring a relatively small holding current. A fault detection circuit is provided to interrupt energization of the solenoid in the event of an excessive flow of current.

Abstract: A power mixing apparatus for mixing current from a first and a second power rail includes a first enabling circuit to provide a first enabling signal, a second enabling circuit to provide a second enabling signal, a first inrush limiter to output a first current in response to the first enabling signal, a second inrush limiter to output a second current in response to the second enabling signal, a first open-circuiting circuit to decouple the first enabling circuit from the first inrush limiter when the first open-circuiting circuit is open-circuited, a second open-circuiting circuit to decouple the second enabling circuit from the second inrush limiter when the second open-circuiting circuit is open-circuited, a first isolation circuit to isolate the first inrush limiter from the second current, a second isolation circuit to isolate the second inrush limiter from the first current, and a direct-current converter to convert the first and the second current in response to the first enabling signal and in respo

Abstract: An exciter for an internal combustion engine igniter plug includes a charging circuit and a discharge circuit; the charging circuit being connectable to a power supply and the discharge circuit being connectable to the plug to produce sparks; the discharge circuit comprising a storage capacitor connected to the charging circuit, a gated solid state switching device connected between the capacitor and the plug, and a trigger means for gating the switching device on and off; the capacitor being discharged when the switching device is gated on and the capacitor being charged by the charging circuit after the switching device is gated off.

Abstract: A system of protection for an electric power distribution system which has at least two parallel power feeders for each electrical phase coupling a source of electrical energy through a contactor device to a load distribution bus comprises a controller, and a parallel feeder current sensor for each parallel power feeder which sense electrical current conducted therein. The parallel feeder current sensors produce output parallel current sense signals proportional to the magnitude of the parallel feeder current sensed, and are coupled to the controller by conductors which communicate the output parallel current sense signals thereto. The controller comprises circuitry which compares the magnitudes of the output parallel current sense signals for each electrical phase.

Abstract: The object is to prevent the degradation of an attraction layer in an electrostatic attraction board system when objects are attracted for a long time. The electrostatic attraction board system comprises a coating layer disposed over the surface of the attraction layer formed of a layered dielectric substance and a pair of positive/negative comb-teeth like electrodes disposed in a laminating structure on the back face of the attraction layer. Objects such as paper sheets are attracted and held on the surface of the coating layer by coulomb force, The coating layer is formed of a plastic material such as biaxial drawn polyester having a low oxygen permeability and a low vapor permeability, and has a volume resistivity of 10.sup.10 .OMEGA.cm or more and thickness of 5 to 50.mu..

Abstract: The coil of an electric control device is energized by ac power controlled by a remotely generated logic level signal through a control module mounted in a cavity in the exterior of the device housing. The module contains a pair of back-to-back silicon controlled rectifiers (SCRs) mounted on a finned aluminum wall of the module which serves as a heat sink. An opto-coupler comprising a light emitting diode (LED) energized by the logic level signal and an opto-triac in series with resistors connected across the gates and cathodes of the back-to-back SCRs provides electrically isolated control of the conduction angles of the SCRs by the logic level signal.

Abstract: A mail-processing machine including an electrical power supply for powering at least one control motor, and a safety locking circuit electrically connected to a cover switch of the machine and co-operating with the electrical power supply to switch the power supply off whenever the cover of the machine is open. The machine includes a chopper electrical power supply comprising at least one power chopper circuit having a control circuit. The safety locking circuit includes at least one electromechanical relay electrically connecting the power chopper circuit to its control circuit, and constituting an integrated on/off mechanism that is approved, cheap, and very compact.

Abstract: An abnormal current cut off circuit for creating a circuit break when an abnormal current flows in a circuit such as a print head driver circuit for a printer. When a driver section 3 is being driven by a power supply circuit 1, the power supply is provided to a driver circuit 2 which drives the driver section 3 via a transistor 5 which is connected in the power supply line and which is turned on by a transistor 7. When the device goes into a standby state, the transistor 5 is turned off, so that the current is supplied to the carriage motor a and the Line feed motor b within the driver section 3 via the fuse 4 and the diode 6 which are connected in parallel with the transistor 5. If an abnormal current then flows during the standby state, the fuse 4 will be broken, and transistor 7 will be turned off so that transistor 5 will also be turned off which ensures that the power supply line is cut completely.

Abstract: In an electric power equipment connected to an electrical power source, a defective ground conductor may result in a dangerous situation for a user. To prevent such a situation, the electric power equipment is provided with a safety electrical assembly having a safety switch mounted between the neutral conductor and the ground conductor on the electric power equipment. The safety electrical assembly also has a female plug provided with a ground socket connected to the ground wire of the power source, a neutral socket not connected to the neutral were of the power source, and one or two power sockets connected to one or two corresponding power wires of the power source. The female plug also has a relay having a normally open switch mounted in series with one of the power wires and a control coil mounted between the one power wire and the neutral socket, and a first light indicator mounted between a stationary contact of the relay and the ground wire in such a manner so as to be visible to the user.

Abstract: An overcurrent protection circuit for a power transistor for generating a main current in response to a gate drive voltage generated by a gate circuit. The overcurrent protection circuit includes a current detection circuit for detecting the main current flowing in the power transistor to generate a detection voltage corresponding to the main current, and a level detection circuit connected to receive the detection voltage for generating a control current corresponding to a difference between the detection voltage and a prescribed value when the detection voltage exceeds the prescribed value. The overcurrent protection circuit further includes a current control circuit connected to receive the control current for limiting the main current by regulating the gate drive voltage based on the control current, and a drive instruction control circuit connected to receive the control current for making the main current zero by controlling the gate drive voltage to an OFF condition based on the control current.

Abstract: An apparatus for reducing power line communication signal attenuation is disclosed. This apparatus provides for reduction of power line communication signal attenuation by balancing reactance between chosen circuit elements and the typical impedances found in a house, structure, or similar entity. The present invention uses a series resonant circuitry to couple the communication signal to the power line. The inductance in the series resonant circuitry is chosen to compensate for the de-tuning effect of the typical power line to which it's coupled in the communication system.

Abstract: A digital circuit interrupter utilizing current transformers for operating power is provided with a re-chargeable battery to power-up the trip unit as well as to power the display after an overcurrent trip occurrence to enable an operator to determine both the magnitude as well as the cause of the overcurrent condition.

Abstract: An overvoltage protection circuit (11) for decoupling circuitry (12) from a voltage applied to an input (38). The overvoltage protection circuit (11) is integrated on an integrated circuit along with the circuitry (12). The overvoltage protection circuit (11) comprises a sense circuit (13), a timing circuit (14), a decoupling circuit (16), and a circuit (17). The sense circuit (13) detects when the voltage applied to the input (38) exceeds a threshold voltage. The timing circuit (14) is responsive to the sense circuit (13) and determines when the voltage exceeds the threshold voltage for a predetermined time. The decoupling circuit (16) is responsive to the timing circuit (14) and decouples the circuitry from the voltage applied to the input (38). The circuit (17) generates a logic signal indicating the circuitry has been decoupled.

Abstract: An apparatus has a liquid level sender providing a sender output signal which varies with a measure of a liquid and which varies with a slosh of the liquid. A main control circuit couples and decouples the sender output signal to a process circuit, the process circuit provides an output signal to a liquid level indicator. Two monitor circuits monitor the output of the process circuit and provide a control signal to the main control circuit if the sender output signal varies from the output of the process circuit by more than a predetermined amount. A switch within the main control circuit decouples the sender output signal from the process circuit in response to the control signal. Sample circuitry within the process circuit drives the output of the process circuit in accordance with a sampled signal when the sender out signal is decoupled from the process circuit.

Abstract: The automatic defensive driving illumination system of this invention automatically illuminates headlights, taillights, side markers and other lights of a vehicle normally activated with the headlight switch. The automatic defensive driving illumination system first determines if the engine of the vehicle is running, determines when the starter for said engine is off and the ignition for said engine is on. If these conditions are present a delayed signal is generated. The delayed signal is combined with a signal from a timer which determines if the time of the day is during the hours of darkness. If the ignition switch is on, the engine is running and the time is during the hours of darkness the automatic defensive driving illumination system will automatically illuminate the headlights, taillights, side markers and other lights of a vehicle normally activated with the headlight switch after the delayed signal is generated.

Abstract: An electrical overstress protection apparatus and method includes the provision of an overstress element (22) comprised of a lamination including a conducting ground path (26) and a dielectric sheet (30) engaging discrete signal paths (16) connected to contacts (44), the sheet (30) containing holes (32) or pores or thread or fiber interstices filled with an electrical overstress protection material (36) with the sheet thickness and hole area in conjunction with area of signal and ground paths and characteristics of the material adapted to provide breakdown and clamping voltages via a path to ground from signal contacts to ground to protect components from excessive voltage levels. Electrical connectors (40,40', 40") incorporate the apparatus in different embodiments of housing (42,42') and contact (44) configurations.

Abstract: In order to improve the operation of a dc transmission unit (GU) between a rectifier (R) and an inverter (I), an extinction angle signal (LS) of the inverter (I) is fed as reference variable to the rectifier regulator (RR). A current signal (ID) of the dc transmission unit (GU) is preferably fed to an inverter regulator (IR) of the inverter (I) as input variable. In addition, the current signal (ID) can be fed as input variable to the rectifier regulator (RR) for the start-up and/or in the event of a malfunction. Another solution consists of a circuit arrangement (S1, S2, S3) for the carrying out of the method.

Abstract: The relay includes an input module capable of receiving 70 volt and 5 amp signals, respectively, from conventional instrument transformers, which are responsive to power line signals at their primaries. Output signals from the input module have specified, standardized levels suitable for electronic processing circuits, i.e. 1.4 volts and 0.1 volt. The output signals from the input module are applied through an accessible connector to a separate processing module which uses those signals in a conventional manner to determine possible faults on the power line. Low-level testing is accomplished by testing the outputs of the input module and by applying test signals simulating the standardized outputs of the input module to the processing module.