Abstract: A compact flourescent lamp in which the level of illumination is controlled by a triac dimmer. Premature turn off of the triac dimmer is avoided through the serial combination of at least one resistor and at least one capacitor forming a snubber placed across the output of the electromagnetic interference filter of the compact flourescent lamp ballast. The snubber dampens oscillations generated within the compact flourescent lamp whereby sufficient power is drawn by the compact flourescent lamp to sustain conduction of the triac dimmer throughout the dimming range of the latter.

Abstract: A resonant mode power supply includes a D.C. voltage source and switching elements for alternatively connecting an oscillating circuit, including a primary winding of a transformer, to the D.C. voltage source and to ground. A first secondary winding supplies the main output voltage of the power supply and a second secondary winding provides a control output voltage. An opto-coupler is included and has a light emitter connected to the second secondary winding, and a light sensor connected to a controller for controlling the switching of the switching elements, wherein the higher the frequency of the switching, the lower the power being supplied by the power supply. Burst mode stand-by is started by the first secondary winding being shunted to the second secondary winding causing the light emitter to emit a maximum amount of light. The controller increases the switching frequency until it exceeds a predetermined maximum frequency.

Abstract: A triac dimmable compact fluorescent lamp having a low power factor. A power feedback circuit coupled between the input and output stages of the lamp ballast creates sufficient current demand to sustain triac conduction at low dim levels. The power fed back from the output stage to the input stage, which includes a voltage doubler, reflects the voltage across the lamp.

Abstract: A triac dimmable compact fluorescent lamp including a power feedback circuit. The power feedback circuit helps to maintain the level of current drawn from the triac to at least the level of the triac holding current especially during low dim levels. In one preferred embodiment, the feedback circuit is fed into a junction joining together a pair of fast recovery diodes for converting the high frequency square wave signal into a unidirectional signal supplied to an inverter. Overboost voltages across a buffer capacitor are minimized during low dim levels.

Abstract: A dimmable fluorescent lamp including a feedback circuit for drawing sufficient current to maintain an appropriate charge across the buffer capacitor. A bypass capacitor provides a path for diverting a portion of the power which would otherwise be fed back to the buffer capacitor during low level dimming. Consequently, overboost voltages across the buffer capacitor during low level dimming are substantially reduced.

Abstract: A circuit arrangement for the high-frequency operation of a discharge lamp comprises a first rectifying circuit (D1-D4) for generating a DC voltage across a first capacitor (C1) from a low-frequency supply voltage. A DC/AC converter (IV) for generating a high-frequency AC voltage at a frequency f from the DC voltage is coupled to a load branch (B) provided with coupling means (T3, T4) for coupling the discharge lamp (Li) to the load branch. The load branch connects a junction point N1 of the DC/AC converter to a junction point N2 between the first rectifying circuit and the first capacitor. A second rectifying circuit for converting a high-frequency voltage generated by the DC/AC converter into a DC voltage is coupled to the first capacitor and to a junction point N3 in the load branch. A control circuit controls the power consumed by the discharge lamp through variation of the frequency f. The coupling means are connected between the junction point N2 and the junction point N3 in the load branch.

Abstract: A wood splitter comprises a fixedly mounted splitting wedge 2 and a pressure plate 4 driven by a hydraulic ram 5,6 so as to feed pieces of wood 3 onto the wedge. Hydraulic fluid is delivered to the ram through the intermediary of a hydraulic-pressure control valve 14. Feed movement of the pressure plate is initiated only when the hydraulic pressure applied to the valve rises above a predetermined value. The pressure plate is returned to its starting position by a spring 23 when the hydraulic pressure falls below the predetermined value.

Abstract: A hydraulic pump motor components including at least two co-acting gears arranged in wells which conform to the gears and which communicate with channels for supply and return oil respectively. To enable the displacement of the pump or motor to be readily changed, the housing of the pump or motor is made in two parts (1, 2) which can be sealingly coupled together. The one part (1), the mounting part, in which the input shaft (3) of the pump, or the output shaft (3) of the motor, is journalled is provided with an inlet and an outlet (10, 11) for supply and return oil respectively. The shaft (3) passes completely through the mounting part (1) and projects from the end surface of the mounting part located in the dividing plane of the housing, for receiving a sun wheel (5). The journal shafts (8, 9) for the planet wheels (6, 7) also project out from the end surface, and channels for supply and return oil respectively discharge into this end surface.

Abstract: A pruning and clearing apparatus comprises a guide bar mounted on a handle. The saw chain of the guide bar is driven by means of a hydraulic motor and a separate portable drive unit comprising a hydraulic pump driven by an internal combustion engine and provided with an oil cooler. The hydraulic pump is connected to the hydraulic motor by lines arranged in the handle.