Abstract: A circuit arrangement for feeding a load (3) from a low voltage energy source (1) via a direct-voltage conversion circuit (2). The direct-voltage conversion circuit periodically takes energy from the energy source by means of a main switching element (10) and supplies this energy as an increased supply voltage (at 12) to the load via an inductive element (9) and a rectifier (11). A starting switching element (15) takes energy for generating the supply voltage (at 12) from the energy source during a starting phase. The circuit arrangement is simple and compact and the energy losses produced are so low that it is economic to use it for energizing a small appliance particularly a small domestic appliance, from a battery or a rechargeable accumulator. A main control circuit (13) is supplied with energy directly from the supply voltage (at 12) and periodically controls the main switching element.

Abstract: A circuit arrangement for reducing an interference current produced by a load (2). The frequency of the interference current is considerably higher than the frequency of a supply voltage source (1) which is coupled to the load. In order to reduce the interference current, a compensation circuit is provided comprising at least one connection branch connected in the leads between the load and the supply voltage source and having each time a series-combination of a capacitor and a controlled signal source. Each signal source supplies a current dependent upon a control signal. The control signals are derived from the current flowing in a lead to the connection branch or away from it. The magnitude and the phase of the currents supplied by the signal sources are proportioned so that the interference current flows for the major part through the connection branch.

Abstract: A circuit for switching current in an inductive load comprising at least one semiconductor switch which periodically switches the current through the load by means of its main current path which is switched alternately to the conductive and to the non-conductive state. A voltage-limiting element for limiting the voltage occuring at it is connected parallel to this main current path. Voltage peaks occuring in the non-conductive state across the main current path are reduced in that the voltage-limiting element (10,11) has a resonance having an oscillation period which is at most approximately 2/3 of the time interval (tn) in which the main current path is non-conducting.

Abstract: A circuit for switching a current in an inductive load comprising at least one transistor (1) which switches through its collector-emitter path the current in the load (7). The base is coupled to the emitter through a voltage-stabilizing element (5) for stabilizing the voltage supplied to the base. A dissipation device is usually added to the circuit for dissipating currents or voltages occurring in a sense opposite to the sense of conduction of the transistor (1). A simplification of the circuit and hence a decrease in the cost thereof is achieved in that the voltage-stabilizing element (5) also serves as the dissipation device.

Abstract: A circuit arrangement for switching a current through an inductive load includes at least one semiconductor switch which periodically switches the current through the load at a switching frequency. The main current path of the semiconductor switch is switched alternately to the conductive and to the non-conductive state. The semiconductor switch has a parasitic capacitance and has connected parallel to it a voltage-limiting element for limiting the voltage applied to it. An increase of the switching frequency is attained with simultaneous operation of the circuit arrangement with minimum losses in the semiconductor switch by using a voltage-limiting element (20, 21) which has an inductive input impedance at the switching frequency.