Abstract: A telecommunications system includes a digital subscriber line, a plurality of analog telephone terminals, at least one digital data terminal, a power supply having a high voltage alternating current input and a low voltage direct current output, and a telecommunications customer service terminal (CST) having a signal input terminal for connection to the digital subscriber line (DSL), having a plurality of analog telephone output terminals for connection to individual ones of the plurality of analog telephone terminals, having at least one digital data output terminal for connection to the at least one digital data terminal, and having a low voltage direct current power input terminal for connection to the low voltage direct current output of the power supply.

Abstract: A telecommunications system includes a customer service terminal having a digital signal-input, a low voltage DC power-input that renders the customer service terminal operative in the absence of an on/off switch, a plurality of analog signal-outputs, and at least one digital signal-output. A digital subscriber line is connected to the digital signal-input, a plurality of analog devices are connected to the plurality of analog signal-outputs, a low voltage DC power supply has its high voltage AC input connected to a high voltage AC power line, and the low voltage DC output of the power supply is connected to the low voltage DC power-input of the customer service terminal. A low voltage rechargeable battery forms a manually-removable portion of the low voltage DC power supply. The battery maintains DC power input to the low voltage DC power-input of the customer service terminal upon failure of the high voltage AC line.

Abstract: A drive system for a brushless DC motor uses pulse width modulation, and phase timing advancement to maintain a constant power output during high speed use. The arrangement is well suited for driving a brushless motor in an electric vehicle and the like.

Abstract: A switching circuit is provided which is to be connected to a power source. The circuit includes a first device, an inductor and a second device, all connected in series. Either a single inductor or a pair of series-connected inductors is connected in series between the first and second devices. One or both of the first and second devices are switched on and off to supply a load with an output voltage. The circuit can also include diodes to prevent harmful reverse current flow and to provide bypasses around the first and second devices. The first and second devices can be semiconductor elements, such as FETs, and particularly MOSFETs. The first device can be an IGBT.

Abstract: A fluorescent lamp is adjusted in illumination intensity by controlling the DC current in the lamp during each alternate direct current flow through the lamp. The magnitude of the current applied to the lamp is set each time the direction of current through the lamp is switched, and the current change between switch times is limited. Inductors are used as current change limiting devices so that in each direction of current flow through the lamp, the current can not rapidly change. The amount of current is set, and the direction of current flow is switched when a current monitor detects that the current through one of the inductors is equal to the current desired for the operating point of the lamp. In this way, uniform selectable illumination levels may be achieved even though the lamp is operating in the negative resistance portion of its resistance characteristic.

Abstract: Flyback power supply with secondary circuit damping during primary charging. This reduces the induced or reflected oscillations into the primary circuit and superimposition onto the primary current so that the latter becomes a monotonically increasing function, permitting and facilitating feedback control.