Abstract: A circuit protection device comprising a chalcogenide glass threshold switching element connected or arranged to be connected between a current carrying line and earth, and a capacitor connected in a series with the switching element.

Abstract: A GPS receiver comprising a pseudonoise generator for simultaneously generating pseudonoise signals respectively corresponding to satellite electromagnetic waves transmitted from two or more satellites, an oscillator for simultaneously regenerating carrier waves of the plurality of satellite electromagnetic waves, and a plurality of demodulators responsive to the regenerated carrier waves and the pseudonoise signals to demodulate individual satellite electromagnetic waves independently, to thereby regenerate data transmitted from individual satellites, each demodulator being operative, during demodulation, to detect a set of phases of one pseudonoise signal and one regenerated carrier wave relative to one satellite electromagnetic wave on time division basis and including a first mixer for mixing of one pseudonoise signal, a second mixer for mixing of one regenerated carrier wave and a filter, whereby a set of phases of one pseudonoise signal and one regenerated carrier wave is changed to another set at timed

Abstract: Protective relay for use in an electrical power system having electrical conductors which are energizable with an AC voltage. The protective relay includes a circuit for sensing the AC voltage to produce an AC output that has zero crossings and a time period between zero crossings, a circuit for supplying an electrical signal representing a preselected pickup value of volts-per-Hertz for the relay, and a circuit responsive to the AC output and to the electrical signal for generating an electrical level as a function of both the time period and the pickup value and for producing an output signal for the relay when the AC output exceeds the electrical level. In this way, the output signal is produced when a volts-per-Hertz value of the AC voltage exceeds the preselected pickup value of volts-per-Hertz for the relay. Other protective relay apparatus and methods are also disclosed.

Abstract: A cycling circuit for cycling a power source alternately between two loads provides switching circuitry having two switches interconnected between the power source and each of the loads. When each switch is in an active state, its respective load receives power, and when each switch is in an inactive state, its respective load does not receive power. A timing circuit controls the activation and deactivation of the switches so that the activation of one switch deactivates the other with the timing circuit establishing directions for each switch's active/deactive state. These durations may be set or selectively variable. A condition sensing element may also be included as part of the timing circuit so that the relative time durations vary automatically in response to environmental conditions such as temperature.

Abstract: In a circuit having a electro-mechanical relay the contacts of which are subject to arcing, a shunt across the electro-mechanical relay configured to begin conducting electrical current across the electro-mechanical relay prior to closing the electro-mechanical relay contacts and to continue conducting electrical power across the electro-mechanical relay for a predetermined time after the onset of separation of electro-mechanical relay contacts pursuant to discontinuance of current flow through the elecro-mechanical relay. An optical coupler is employed to detect the current flow through the relay coil and activate a shunt device to initiate current flow around the electro-mechanical relay. The shunt device is configured to be substantially non-current load carrying while the electro-mechanical relay is closed. Utility is found in protecting relay contacts against damage due to arcing.

Abstract: The safety circuit of the present invention is connected to a drive control circuit for applying driving signals to a plurality of switching devices connected to respective stator coils of the brushless D.C. motor at a predetermined timing, and sequentially supplying a driving current to each phase of the stator cells. The safety circuit is adapted to simultaneously detect the driving signals and generate a cut-off signal for cutting off the driving current supplied to each of the stator coils in the event that the driving signals are simultaneously applied to the switching devices in controlling a driving operation of the brushless D.C. motor.

Abstract: A circuit arrangement for protecting the antilocking electrical system from overvoltages developed in the vehicle's electrical systems. Such overvoltages can be caused by a load dump and can lead to destruction of the vehicle's electrical system. To sense an overvoltage condition, a test circuit is provided which is connected to the vehicle's electrical system. The voltage test circuit provides an output signal when the voltage of the vehicle's electrical system exceeds a first threshold value. This output signal is used to switch the final stage of the antilocking electrical system. The overvoltage is thereby conducted directly to one or more low-resistance solenoid valves which limit the voltage in such a way that it no longer presents any danger to the vehicle's electrical system.

Abstract: An arc suppression circuit for a switch carrying a load current includes a MOSFET having a drain connected to a first contact of the switch and a source connected to a second contact of the switch. A biasing capacitor is coupled at one end to the drain and at another end through a damping resistor to the gate, such that when the switch contacts are opened, the interrupted load current passes through the biasing capacitor to charge an inherent gate-to-source MOSFET capacitance for turning on the MOSFET and shunting the load current around the switch. A biasing resistor, connected between the gate and the source of the MOSFET, subsequently discharges the gate-to-source capacitance, turning off the MOSFET and terminating the shunted load current after the contacts of the switch have separated by a distance sufficient to preclude arcing.