Abstract: A temperature controlled circuit including a thermistor located in one branch of a bridge circuit containing several resistors, an operational amplifier, all combined in such a manner that a resistor is inserted in parallel with the thermistor to lower its impedance. The branches of the bridge circuit are also arranged in such a way that three branches have a nominal resistance approximately equal to the resistance of the thermistor in parallel with its fixed resistance at room temperature, while the fourth leg on the branch in series with the parallel thermistor and resistance across the voltage source will have a resistance nominally in the range of one-third of the paralleled resistor and thermistor. The arrangement is such that most any thermistor can be utilized merely by changing its parallel resistance, and the operational amplifier will operate with the thermistor over a wide temperature range.

Abstract: A CMOS circuit (10) for preventing overvoltage between two supply nodes (12,14) makes use of vertical NPN bipolar transistors (80,84) for their current-carrying capability. Zener diodes (16,18,20,22) and a resistor (24) generate a sensing voltage which is amplified by a vertical bipolar transistor (28) and coupled to one input of a comparator (40) which has the other input at a bias voltage node (52) of a voltage divider (54,56,58,60). The comparator output (50) is coupled to the input of a transimpedance transistor (72) which drives the input current of a current mirror (66,74). The output (78) of the current mirror turns on the current-carrying transistors (80,84). Positive feedback for latching is provided by connecting the common gates of the current mirror transistors to the gate of a feedback transistor (86) which has its current path connected between the one supply node and the base (26) of the first bipolar transistor.

Abstract: A plurality of electrical devices are controlled by a single operation switch. A transfer switch selectively connects the operation switch with one of the electrical devices. When a push button switch is actuated, the connection of the transfer switch is controlled so as to connect the operation switch with another of the electrical devices for a predetermined period of time.

Abstract: In an electromagnetic launcher such as a railgun for propelling a projectile at high velocity, a counterpulse energy recovery circuit is employed to transfer stored inductive energy from a source inductor to the railgun inductance to propel the projectile down the railgun. Switching circuitry and an energy transfer capacitor are used to switch the energy back to the source inductor in readiness for a repetitive projectile propelling cycle.

Abstract: A tri-state driver circuit 10 for selectively driving a node of a device under test by applying and switching between two reference voltages, and for selectively operating at a high impedance output state. Two current sources 16 and 18 provide a bridge current that flows through a diode bridge 20 to establish, at nodes A and B, voltages that equal two reference voltages, DRH and DRL. The diode bridge includes resistors R11 and R16 across which the bridge current is switched to accommodate small voltage swings, and also includes clamp diodes CR3-6 to accommodate large voltage swings. A current switch 22 controls the direction of the bridge current and the selection of which of the two reference voltages appears at node A. A current sink 36, 38, and 40 monitors the average voltage of the diode bridge and adjusts it to equal the average of the two reference voltages.

Abstract: In a power supply system having a grounded neutral and supplying service equipment through a distribution transformer, a ground voltage suppression device comprises a saturating inductor or like non-linear impedance device connected between the secondary neutral conductor and a normal ground conductor so as to define therewith a neutral-to-ground current path which presents a high impedance to current flow for applied voltages up to a predetermined level.

Abstract: A control circuit is provided for applying energy to operate a circuit interrupter in response to, and a selected time after, the onset of overcurrent in an alternating-current line. The control circuit includes a transducer for producing output current proportional to the current in the line. The power supply includes an energy storage circuit that stores energy derived from the output current. The stored energy, which is maintained within a first range when there is no overcurrent in the line, energizes the power supply. A time-current trip signal generator circuit responds to output current representative of moderate overcurrent in the line by producing a trip signal after the passage of a time period that is inversely related to the overcurrent.

Abstract: A lightning arrester insulator in which a voltage non-linear resistor having a major constituent of zinc oxide is integrally fixed in a longitudinal bore in the insulator with a layer of an inorganic adhesive agent which is interposed between an outer surface of the resistor and an inner wall surface of the insulator defining the longitudinal bore. A contact angle of the adhesive agent layer defined by each end face thereof and an associated end part of the inner wall surface is held within a range of 10 to 60 degrees. To establish the contact angle, at least one of the end face of the adhesive agent layer and the associated end part of the inner wall surface of the insulator is inclined with respect to the longitudinal centerline of the longitudinal bore. Each end surface of the voltage non-linear resistor is spaced from the corresponding end of the adhesive agent layer axially inwardly along the longitudinal centerline of the longitudinal bore.

Abstract: A static discharge device for preventing an electrostatic shock comprising a conductive body to be grounded to the ground body, a resistance element contacting with the conductive body and having a resistance value to restrict a current value when the conductive body is contact with the ground body by the person, and an insulating material provided between the conductive body and the contacting portion held by the person so as to elongate a creeping distance between the conductive body and the human body.

Abstract: An over current of an output transistor circuit of a voltage regulation of a vehicle mounted charging generator due to a short-circuit of a field winding thereof is detected and a capacitor is charged when the detected current is larger than a predetermined value. The voltage of the capacitor is compared with a reference voltage and the output transistor circuit is cut off during the voltage of the capacitor is larger than the reference voltage, whereby a breakdown of the output transistor circuit is prevented.

Abstract: The magnitudes of currents in the armature and field windings of a separately excited d-c motor are compared, and a fault signal is produced in response to the field current magnitude either rising above a first reference level (which varies as a first predetermined function of the armature current magnitude) or falling below a second reference level (which varies as another predetermined function of the latter magnitude).

Abstract: An alternating current limiting apparatus is disclosed which normally forms first and second series circuits connected in parallel with each other between different kinds of power system lines. The first series circuit is resonated with a reactor and a capacitor at a line frequency to directly interconnect the power system lines. The second series circuit is composed of a capacitor or a reactor and two resistors. Between the interconnection of the reactor and the capacitor of the first series circuit and the interconnection of both resistors, a closing device is connected. Upon the occurrence of a fault of either of the power systems, the closing device is thereby actuated to form a parallel resonance circuit with the combination of the reactor or capacitor of the first series circuit and the capacitor or reactor of the second series circuit to limit current flowing between the power system lines.

Abstract: An electric power source for use in an electrostatic precipitator includes a first high voltage DC source having an output terminal adapted to be connected to discharge electrodes of the electrostatic precipitator. An inductor is connected at its one end through a coupling capacitor to the output terminal. A controlled rectifier is connected at its an anode to the other end of the inductor and has a grounded cathode. A diode is connected in a reversed parallel to the controlled rectifier. There is also provided a second high voltage DC source having a high output impedance and connected to the inductor, and the controlled rectifier is turned on and off by a controller.

Abstract: A power supply is provided for energizing a trip signal generator and for selectively operating a device in response to the detection by the trip signal generator of overcurrent in a alternating current line. The power supply receives input of full-wave rectified current that is directly proportional to the alternating current in the line. A regulator circuit is also provided to power the trip signal generator and other circuitry. When current initially flows in the line the regulator rapidly produces an output voltage approximately equal to the input voltage up to a first voltage level. When the input voltage exceeds that level, the output voltage of the regulator increases at a slower rate than the input voltage to permit regulation of the output voltage. When energized, the output voltage is regulated at a predetermined constant level. The power supply also includes an energy storage circuit for supplying the input voltage to the regulator and to a circuit interrupter when desired.

Abstract: A single-phase or multi-phase inverter protected with respect to the rates of increase of current and voltage, the said inverter comprising a filter capacitor and a choke protecting with respect to the rate of increase of current, as well as, members protecting with respect to the voltage increase rate. In order for it to be possible to discharge the energy stored in the magnetic field of the choke and in the capacitor, between the change-over steps of the inverter substantially without losses, for each phase, there is a series connection of the capacitor and a diode connected in parallel with only one semiconductor switch and a diode is connected between the connection point between the capacitor and the diode, and one terminal of a storage capacitor. The energy in this way transferred to the separate storage capacitor can then be transferred to the filter capacitor by use of a breaker.

Abstract: Circuitry for use in a power supply of the type which includes a power switching means and uses a waveform of predetermined shape to control the power switching means such as in a first mode the supply regulates its output voltage and in a second mode controls the current in the power switching means. The circuitry attempts to turn the supply off in response to an overvoltage condition at its output and failing that provides a short circuit path so that current sufficient to cause the fuse in the output to open will flow therethrough.

Abstract: A protective relay for providing an infinitely variable family of curves for use in ground-fault protection. In one embodiment, the protective relay includes a saturable reactor across the output terminals thereof. The saturable reactor impedance varies in accord with the load or fault current such that a trip characteristic based on the zero sequence current and the load or fault current is obtained. The trip characteristic is selected by a potentiometer that limits the amount of dc current to the saturable reactor. Once established by setting the potentiometer, the trip characteristic defines the amount of 3I.sub.O neutral current, as a function of three-phase current, necessary to operate the protective relay. Varying the potentiometer setting provides the infinite family of curves.

Abstract: An energy transfer network is used to ensure reliable operation of a low water sensing system for a boiler. The energy transfer network provides a sufficient time interval to make sure that wave action and boiling within the boiler do not simulate the loss of water. The energy transfer network is structured to be discharged in the event water actually drops below an appropriate level. The energy transfer network provides for the continuous presence of water so that boiling action does not simulate an artificially high (presence of) water level.

Abstract: An integrated circuit (IC) carrier having uniform conductivity and the ability to securely hold an IC in a predetermined position within the carrier is disclosed. The IC is securely held inside a closed enclosure without using the IC leads to support the IC. Additionally, a viewing window which allows the reading of information printed on the IC from outside the closed enclosure is disclosed. The enclosure is formed as a one-piece object which additionally includes a living hinge, a latching system, structure which aids stacking, and structure which facilitates opening of the enclosure by automated means.

Abstract: The invention relates to a circuit arrangement for actuating exciting coils for electromagnetic switchgear. A transistor is connected in series with the exciting coil, as an electronic switch. Parallel with the series connection are a capacitor and a clock generator, which opens and closes the transistor with a certain frequency. Thereby, upon opening, a defined turn-off delay of the electromagnetic switchgear, and upon switching on, with the use of a timing element which at first deactivates the clock generator, the effect of a d-c saver circuit for electromagnetic switchgear can be achieved.