Abstract: Loads, such as power relays controlling wipers, windows and lights are connected to an automobile battery through individual transistor drives that are controlled by a microcontroller. A switch, connected to the microcontroller, is operated to activate each drive. The microcontroller checks the load characteristic when each drive is activated and inactivated. When the load is inactivated, it is part of a resistance network producing a test voltage that is digitally converted and supplied to the microcontroller, which compares the test voltage to a stored voltage to determine if the load is correct. An analog multiplexer is controlled by the microcontroller to select the voltage produced for each load.

Abstract: Multiple latching relays are driven on their first side by all but one of the parallel outputs of a shift register. Each relay on the same shift register is driven on its second side by the remaining parallel output of the shift register. A clock signal is fed to all shift registers and causes each shift register to shift all of its information one cell on the selected edge of the clock signal. A latch signal or blanking signal is used to prevent the shift registers from outputting their information to the relays during shifting. A serial data message is inputted to the first shift register and then from the first shift register sequentially to all of the other shift registers. The information in the serial data message is such that after shifting of all shift registers is complete the appropriate signal will be on each side of each latching relay to cause it to either change or remain unchanged.

Abstract: A circuit for the remote control of solenoid operated valves in an irrigation system reduces by one half the amount of wire required for the system. At least one pair of first and second solenoids are connected to a source of supply of alternating curent, typically through a low voltage circuit. A switching circuit selectively connects the source to the solenoids through a conductor having a diode network at either end of the conductor. One of the diode networks comprises a pair of diodes connected in anti-parallel relation across the switching circuit, and the other of said diode networks comprises a pair of oppositely poled diodes respectively connected between the conductor and a corresponding one of the solenoids.

Abstract: A circuit arrangement having a purely capacitive power supply, at least one power consumer, and a control element for causing power to be supplied to the power consumer. The power supply, the power consumer and the control element form a series circuit. The power consumer has a relay activated by a switching transistor, the switching transistor is connected to the control element. The purely capacitive power supply has a series capacitor for defining the current flow in the series circuit. The circuit arrangement may have a plurality of power consumers connected in series with each other and in series with the power supply and the control element.

Abstract: A switch connected between two voltage sources and responsive to a sensing circuit. The switch includes a transistor which operates to interchange the electrical connection of the two voltage sources from parallel to series upon the sensing circuit signals the need for more voltage. The two sources are normally in parallel to increase the cost efficiency and energy efficiency of the amplifier and power supply.

Abstract: Switching apparatus for matching an electrical load to the voltage output of a wind-driven generator in which the loads are an even number of batteries or electrolytic cells (16). The apparatus includes switching units (10) each having four terminals. Each switching unit has two switching states A and B, the odd numbered switching units (10a, 10c etc.) having pairs of batteries or cells connected between first and third, and second and fourth terminals so that when the switching unit is in State A, the batteries are in parallel and when in state B they are in series. The even numbered switching units (10b etc.) each serve for the interconnection of adjacent pairs of batteries in series or parallel.

Abstract: Temperature responsive power supply apparatus for electrical resistance heating, e.g. for weld stress relief, has a power supply transformer comprising first and second secondary windings in series with one another and first, second and third conductors for connecting the secondary windings to heating elements. A pair of temperature sensors provide temperature signals corresponding to the temperatures of heated zones heated by the apparatus, and a pair of control units responsive to the temperature signals control the current flow through the conductors. A switch enables one or both control units to regulate saturable reactors or the like in series with the conductors, whereby the control unit can regulate two respective heating circuits each including one of the secondary windings or one of the control units can regulate a heating circuit including one or both of the secondary windings. The apparatus provided improved versatility for heating one or more large or small pipe welds.