Abstract: A DC to AC converter capable of producing up to three-tier waveforms includes a first transistorized switching amplifier operable to a first condition, for charging a first capacitor to +2E volts, concurrent with applying +E volts to a first terminal, and connecting a DC supply of -E volts to the positive plate of, and in series circuit with, a second capacitor (previously charged to have a voltage drop thereacross of -2E volts), the series circuit being connected between a reference and second terminals, for applying -3E volts to the second terminal. The first switching amplifier is operable to a second condition for charging the second capacitor to -2E volts, concurrent with applying -E volts to the second terminal, and applying +E volts to the negative plate of the first capacitor, the positive plate of which is connected to the first terminal, for applying +3E volts to the first terminal.

Abstract: A switching amplifier includes a grounded collector NPN Darlington amplifier having a main current path connected between a terminal for receiving an operating voltage and an output terminal, and an input base and output emitter electrodes across which a series circuit of the main conduction of an NPN transistor and a floating DC voltage supply are connected. In response to a switching signal applied to its base electrode, the NPN transistor turns on to connect in "bootstrap" the DC voltage supply directly across the base and emitter electrodes of the Darlington amplifier, for turning on and operating the Darlington amplifier at its maximum power and rated voltage or current capability.The field of the invention relates generally to switching amplifiers, and more particularly to high-power switching amplifiers.Many present high-power semiconductor switching amplifiers or circuits include in their output stages a combination of NPN and PNP transistors.

Abstract: A voltage waveform synthesizer whereby an ac waveform (which may be varied in frequency) is synthesized from dc or unidirectional voltages in a programmable fashion, the power carried by the waveform being controllable from zero to some maximum value and the harmonic content of the waveform also being controllable. The synthesizer per se is described and it is shown in combination with a rotating electric machine to provide, for example, a variable speed drive mechanism.

Abstract: A remote location actuator that is adapted to receive an input signal, to ascertain whether or not the input signal contains a message upon which the actuator should act, and to effect some predetermined act upon receipt of an appropriate message. By way of illustration, the signal may be in the form of, say, two trains of pulses that may be produced by a telephone bell, the message being contained in the number of pulses in each train. Input to the actuator may be in the form of electromagnetic transfer from the telephone.

Abstract: An electronic motor that accepts single-phase power and converts the same to polyphase power which is delivered to a polyphase winding of the machine. The electronic motor includes an electronic synthesizer. The synthesizer is shown in the context of an electronic motor, but in a wider context as well.

Abstract: A variable speed electronic motor having wound polyphase armature and field windings each of which is energized by a polyphase source whose voltage and frequency are variable in a controlled fashion. Provision is made to control the excitation of the armature and field windings so that the torque output is optimized for all loads and speeds. Also, the machine disclosed can be made to function in a generating mode; hence, there can be flow of both electrical and mechanical energy to and from the machine and the amount of each can be carefully regulated. In addition, a variation of the machine, acting purely in a generating mode, can be programmed to regulate electrical output of the machine independent of the angular velocity of the machine, and output power can be similarly regulated, all within reasonable limits. Also, for some requirements one winding can be energized at a constant frequency and voltage and the other can be excited at variable frequency and voltage.

Abstract: A security method for controlling the passage of persons and objects between two areas, this method employs a controlled space. Prior to admitting, during the presence and subsequent to exiting of a person to this space, the contents of the space are monitored and examined.

Abstract: A linear amplifier that is able to yield a maximum output voltage substantially greater than the breakdown voltage of the individual amplifying elements used and substantially greater than the voltage of a primary electric energy source that powers the amplifier. The amplifier consists of a plurality of stages connected in cascade, each stage, in turn, controlling the voltage level at which subsequent stages operate.

Abstract: An electric power supply wherein electric energy is processed using high frequency techniques to provide as output electric energy whose frequency and/or voltage are programmable. The apparatus described can, for example, accept as input low frequency energy (e.g., 60 Hz) at available voltages (e.g., 120/240/480) and can process the same through intermediate high frequency steps to provide an output at power levels and voltages found in industrial power circuits, that can be varied both in frequency and voltage; or the input can be processed in like manner to give, for example, a very high voltage pulsed output.

Abstract: The specification discloses a chair having a seat seated on spaced side rails above an auxiliary seat supporting surface which is spaced slightly below the seat and which shares the load imposed on the seat by a person sitting in it with the side rails and their supporting stretcher, yet allows the seat to give slightly so that the seat feels comfortably yielding.

Abstract: A multi-node network having two sets of SCRS, each set comprising a pair of parallel-connected, oppositely-polarized SCRs, the sets being electrically joined to form a common connection whereby electric current can flow through one pair to the common connection, thence to a load and/or to and through the other pair, or electric current can flow through said other pair to the load. Each SCR of the SCR pairs is triggered by transient signals such that the common connection can receive continuous power through either set of SCRs of the power and the connection can be switched between sources.