Abstract: A drive current circuit for a switching power transistor which allows the controlled turn off of the transistor without affecting transistor turn on. The drive transformer has two cores one of which follows a linear magnetization characteristic and the other of which has a relatively high permeability. The input and output windings of the drive transformer are wound on both cores. A turn off winding is also included which is wound only on the high permeability core. A source of turn off charge is directly coupled to the transistor. Shorting of the turn off winding initiates the controlled turn off of the transistor.

Abstract: A circuit for holding the voltage across a rapidly switched semiconductor element such as a transistor used in an inductive circuit to substantially twice the voltage of an input source when the element is switched to its nonconducting state. Also included is circuitry for recovering and returning to the input source the energy stored in the inductance and wiring of the inductive circuit.

Abstract: Apparatus for packaging articles by enclosing an article between two layers of sheet materials, each having cohesive coatings thereon which includes two spaced sets of relatively small independently mounted rollers for feeding the sheet materials and cutting and sealing heads disposed in close proximity to said sets of rollers and means for controlling the sheet feeding rate and the cutting and sealing operation to produce packages of any desired length.

Abstract: A circuit for providing a regulated a-c or d-c output voltage from an unregulated a-c input voltage. A series inductance is connected between the regulator input and the regulator output to support the difference in voltage between the unregulated a-c input voltage and the regulated a-c or d-c output voltage. A controllable shunt reactance is connected to the source of input voltage, through the series inductance, to vary the current through and the voltage across the series inductance. Control circuitry controls the magnitude and the capacitive/inductive character of the current which the shunt reactance draws through the line inductance, as required, to establish and maintain the regulated output voltage at the desired output current.

Abstract: A circuit for providing a regulated a-c or d-c output voltage from an unregulated a-c input voltage. A series inductance is connected between the regulator input and the regulator output to support the difference in voltage between the unregulated a-c input voltage and the regulated a-c or d-c output voltage. A controllable shunt reactance is connected to the source of input voltage, through the series inductance, to vary the current through and the voltage across the series inductance. Control circuitry controls the magnitude of the current which the shunt reactance draws through the line inductance, as required, to establish and maintain the regulated output voltage at the desired output current.

Abstract: A circuit for providing a regulated square wave output voltage and a regulated DC output voltage or both. An AC source energizes a switching circuit, having a variable switching rate, which connects a capacitor in voltage clamping relationship to an AC load for both half cycles of the AC voltage thereacross. This switching rate is controlled in accordance with the time accumulation of an electrical quantity, in the present instance the voltage across the AC load. The DC voltage across the capacitor attains a predetermined equilibrium value when the frequency of the AC output voltage is equal to the frequency of the AC source. If the DC capacitor voltage and the AC output voltage derived therefrom deviate from their equilibrium values, as, for example, because of a change in the level of load current, there occur transient changes in the switching rate of the switching circuit which result in changes in the phase displacement between the AC input voltage and the AC output voltage.