Abstract: A circuit interrupter provides a conducting path between two conductors and interrupts the conducting path in response to overcurrent conditions in the conductors. The interrupter includes a magnetic core around which the conductors are disposed. Each conductor is electrically coupled to an arc runner and a spanner is biased into contact with the arc runners to compete a conducting path between the conductors. A secondary response mechanism is provided adjacent to the core and includes arms extending around the core and a magnetic body. In response to overcurrent conditions of a first magnitude the body of the secondary response mechanism is attracted to the core causing the arms to displace the spanner out of contact with the arc runners. In response to overcurrent conditions of a second magnitude, such as due to direct short circuits, the spanner is repelled rapidly to a non-conducting position and the secondary response mechanism is attracted to the core to hold the spanner in the non-conducting position.

Abstract: In accordance with the present invention, an output current limit circuit for protecting a power MOS output device of an integrated circuit from an excessive drain current comprises a power MOS device 110, sensing circuitry 30 to sense a predetermined trigger current, and limitation circuitry 20 to reduce a gate-source voltage on MOS output device 110 to a predetermined approximately fixed value. A drain current I.sub.D flows through power MOS device 110 from output terminal 102 in response to the gate-source voltage. A short circuit condition may allow an excessive amount of drain current I.sub.D to flow through output terminal 102. The gate-source voltage is reduced in response to sensing the trigger current. Reducing the gate-source voltage raises a drain-source resistance of MOS device 110 and reduces drain current I.sub.D so that MOS device 110 is not damaged by the short circuit condition.

Abstract: A synchronization adder circuit for digital data communication includes an A/D converter, a waveform-shaping circuit, a square circuit, a low-pass filter, and an adder. The A/D converter samples at given sampling points in time per sampling cycle a received signal transmitted through a plurality of subcarriers to digitize sampled values to provide digital signals. The waveform-shaping circuit then waveform-shapes the digital signals from said A/D converter without decomposing them with respect to each subcarrier. The square circuit squares the output signals from the waveform-shaping circuit. The low-pass filter removes a given high-frequency component from output signals from the square circuit. The adder adds values of output signals from the low-pass filter at each sapling point for preselected sapling cycles to determine the samples suitable for reproduction of original data.

Abstract: Upon the occurrence of a fault on the first distribution line, a faulty section on the distribution line is pinpointed, then a tie point switchgear at the tie point between the first distribution line in which the fault occurred and the other normal second distribution line is closed to form a loop distribution system. Then, a switchgear adjacent to the fault point on the first distribution line is opened. An opposing switchgear adjacent to the fault point is opened on the condition that the fault occurrence continues after having been linked to the second distribution line. The above procedures are executed before the opening of the circuit breaker installed on the distribution bus bar.

Abstract: A surge protector for coupling exposed (to power surges) data communication end ports having a plurality of bi-directional data lines, and protected data communication end ports having a plurality of associated bi-directional data lines. The surge protector includes a plurality of exposed end terminals, each exposed end terminal for connection to a data line of the exposed port, and a plurality of protected end terminals, each protected end terminal for connection to an associated data line of the protected port. The surge protector includes a plurality of transient surge protection elements. Each transient surge protection element is connected across one exposed terminal and a ground, and short circuits current to ground when voltage on the exposed terminal reaches a threshold limit. The surge suppressor also includes a plurality of opto-isolation elements, each connected between a connection for a transient surge suppressor element and a protected terminal.

Abstract: An overcurrent detecting circuit provided within a battery pack detects any overcurrent flowing in a circuit electrically connecting the battery and connection terminals. Upon detection of any overcurrent by this overcurrent detecting circuit, a switch circuit intercepts the electric connection between the battery and the terminals, and opens the so far closed circuit.

Abstract: Circuit for protection of an amplifier stage comprising circuit switching means for turn-off of the stage and piloted through a logic gate OR by a monostable, which generates upon arise of abnormal operating conditions turn-off command signals having a predetermined duration.A sensing circuit upon persistence of abnormal conditions at start-up or during normal operation also sends turn-off signals through the logic gate OR after enablement through a gate AND.The signals of any enablement at the logic gate AND arrive through a logic gate OR from a window comparator coupled with stage start-up members, from the monostable, and from the output of said logic gate AND as a confirmation signal.

Abstract: A input circuit provides ESD protection to an integrated circuit comprising a V.sub.dd pad, a V.sub.ss pad, a plurality of input and output pads, a V.sub.dd power rail, and a V.sub.ss power rail. A large diode sufficient to carry ESD current is placed directly between the V.sub.ss pad and the V.sub.dd power rail, and the input pads are connected to the V.sub.dd power rail through respective diodes.

Abstract: An overvoltage protection circuit employs a series of semiconductor switching elements, each element having a control terminal and two main conduction terminals, in a totem pole configuration and two potential dividers whose tapping points feed, respectively, the control terminals and the main terminal junctions of the switching elements. Both the series of switching elements and the two potential dividers are connected between a reference node (zero volts) and a node to be protected from an electrostatic discharge. The resistive elements of the potential dividers are so arranged that, in the absence of a static discharge, all switching elements are cut off and experience a substantially equal voltage across the respective main terminals. In this way, the circuit may be usefully employed in integrated circuits which are based on a low-voltage integration process but which have also a high-voltage-supply rail (e.g. 30 V). The switching elements may be bipolar transistors, and preferably Darlington pairs.

Abstract: An assembly mounted to a grounded chassis and connected between first and second multi-conductor cables carrying a plurality of transmission line-pairs. The assembly provides transient voltage surge protection to the plurality of line-pairs. The protective circuitry is mounted on a printed circuit board along with connectors and is contained within an insulative housing. The connectors of the assembly are mounted to the printed circuit board and are matable with connectors terminating multi-conductor cables so that the protective circuitry is interposed in the line-pairs carried by the cables.

Abstract: A power supply circuit receives and rectifies a three phase power source. A first capacitor is coupled to filter and store the rectified three phases and supply the stored energy to a DC/DC converter. The first capacitor is large enough, when all three phases are present, to filter the rectified input power and supply rated voltage to the DC/DC converter between peaks in the phases, but not too large as to adversely affect the power factor. However, when one phase drops out, additional capacitance is required to maintain rated voltage to the DC/DC converter during the periodic absence of the one phase. Thus, a switch and a second capacitor are connected in series with each other and in parallel with the first capacitor. In response to absence of one of the phases, the switch is activated to couple the second capacitor to filter and store the rectified two phases and supply the stored energy to the DC/DC converter.

Abstract: A fused disconnect switch including a plurality of maintenance and installation enhancing features is disclosed. For example, a bipolar LED is provided as an alarm indicator so that the fused disconnect switch will function in power distribution systems which operate on both positive and negative voltages. Additionally, a manual test tab is provided for checking the alarm circuitry and a viewing window is provided so that the presence or absence of a fuse in the fused disconnect device can be ascertained without removing the fuse holder.

Abstract: A circuit for preventing switching voltage transients from damaging the IGBT during short circuit shut off, utilizing electronic gate control which decrease the rate of fall of the gate voltage of the IGBT only when a short circuit condition is sensed, thereby avoiding any losses during normal switching operation. In a first embodiment, a considerably higher value of gate resistor is switched-in in series with the gate resistor during a short circuit condition. In a second embodiment, a considerably higher value of external capacitor is switched-in in parallel with the IGBT gate input capacitance during a short circuit condition.

Abstract: An automatic power line monitor system is disclosed for use in monitoring the electrical voltage supplied to an electrical system or appliance by monitoring the supplied electrical voltage and preventing the supplied electrical voltage from reaching the electrical system or appliance when the supplied electrical voltage is not within a predetermined range and for automatically restoring the supplied electrical voltage to the electrical system or appliance when the supplied electrical voltage is within the predetermined range.

Abstract: Disclosed is a surge suppression system employed in a system comprising Hot and Neutral power line segments coupled via a filter to protected electronic circuitry. The surge suppression elements include a spark gap comprising a first electrode connected to the Neutral line segment and a second electrode connected to the ground potential; and a voltage clamping device electrically connected to the Hot and Neutral line segments at a point which is electrically closer to the protected electronic circuitry than the spark gap. The invention permits the filter to ring up to high voltages, and provides a mechanism whereby electrical breakdown occurs at a prescribed point. Surge suppression is provided after the filter by the single ungrounded clamping device.

Abstract: A protective circuit unit includes an analog switch connected to a DC power line which is connected to the power source circuit of said electronic device and a main constant voltage diode connected in parallel to the DC power line, wherein an input applied to a control terminal of the analog switch is controlled by current flowing in the constant voltage diode so as to turn off the analog switch when a supply voltage is higher than a predetermined value.

Abstract: A parallel to serial converter (10) uses a data hold-time indicator (22) to indirectly observe the timing relationship of the data and clock applied to a data register (14) embedded within an integrated circuit. The incoming data word is converted from CMOS to ECL logic levels (12) and applied to the data register. The register holds data for a multiplexer (16) that rotates through the output data from the register for providing a serial data output signal. A flipflop circuit (18) clocks the serial data output signal. The data hold-time indicator circuit monitors one register input and generates a recurring pulse having a width that reflects the data hold-time at the embedded register. By indirectly observing the timing relationship, the externally sourced data timing can be calibrated to meet the setup and hold-time requirements of the data register.

Abstract: The present invention is directed to a system for sensing fault current flowing through a person who touches an exposed conductor in a cable connecting a machine to a power distribution center wherein the power distribution center has a number of power cables for connecting a number of machines thereto. Each power cable has a different frequency impressed thereon by an oscillator which frequency is transmitted through an electrical path including the power center if the operator touches the fault. A sensing circuit for each cable is connected in the electrical path and tuned to only the frequency applied to that cable. When the sensing circuit detects that frequency, the sensing circuit interrupts power to the cable. If, for some reason, the sensing circuit fails to interrupt power to the cable, within a selected time interval of less than one-half second, a backup system interrupts power to the entire power center.

Abstract: A leakage voltage inductor serves as an electrical safety protection device used to send an instant alarm or to cut off the power when a leakage is detected in an electric appliance, the device being used to send the alarm and to cut off the power automatically whenever a potential difference of more than 6V is detected between the housing of the appliance and the ground on which a person stands, for electrical safety protection purpose.

Abstract: A new and novel system for protecting people and property against electrical shock. It includes a number of preferred and other embodiments which have this as their goal, but which represent a number of distinctive and novel approaches to solving prior art problems. By way of example only, and without limiting the scope of this invention, these approaches include novel immersion detecting circuits, broken wire test circuits, electromechanical circuit breaking means including coil/plunger arrangements, and relay circuit breaking mechanisms cooperative with associated circuitry, all of which are able to be incorporated as a system wholly within the load (appliance) and its associated cord set (including a "plug").