Abstract: A device (1) for supplying electric power to a load (4) connected to the device (1) in a power-on mode comprises a driver stage (7), a control unit (9), adapted to supply turn-on pulses to the driver stage (7), and an output stage (12) with a switching transistor (1) which can be driven into its conductive state for a time interval (T.sub.EIN) by the driver stage (7) in the power-on mode when turn-on pulses occur, and which can be driven into its non-conductive state after expiry of the time interval (T.sub.EIN), the driver stage (7) being also adapted to monitor the operating temperature (T.sub.S) of the switching transistor (11) and to activate a power-off mode when the operating temperature (T.sub.S) of the switching transistor (11) exceeds a first limit temperature (T.sub.G1), in which power-off mode the switching transistor (11) is permanently driven into its non-conductive state by the driver stage (7) in spite of the occurrence of turn-on pulses (I.sub.

Abstract: A simple and effective stereophonic transmission system (1) wherein the transmitter (2) alternatively encodes successive block periods of a block signal with samples of the left-hand channel signal (L.sub.in) and the right-hand channel signal (R.sub.in). At receiver side, the left-hand and right-hand stereo signals are decoded from the encoded block signal by alternate integration and peak detection of positive and negative received pulses, the pulse widths of the received pulses corresponding to amplitudes of the transmitted samples. When detecting the pulses for one stereophonic channel, the corresponding other stereophonic channel is blocked.

Abstract: A circuit arrangement for charging batteries comprises a charging current source for supplying charging current pulse trains. The circuit arrangement comprises a first detection device for determining an actual voltage dependent upon a variable reference voltage, which actual voltage is proportional to the average sum voltage of a battery. The first detection device supplies a detection signal corresponding to the detection result and which controls the duty cycle of the pulse-shaped control signal which can be generated by a control pulse generator. The control pulse generator varies the duty cycle dependent on the detection signal when the actual voltage increases or the reference voltage decreases, in a manner such that the ratio between the charging period and the charging pause in a charging pulse train is reduced. A device is provided which enable the reference voltage to be varied in the same sense as the duty cycle depending on this duty cycle.

Abstract: A circuit arrangement (12, 13) for the electronic level control of a sound signal includes an amplifier circuit (14), the gain of which can be controlled in dependence on a variable direct control voltage, and a voltage-adjusting stage (15) for generating the variable direct control voltage. The amplifier circuit is formed by a CMOS inverter (14), of which the supply voltage connection (21), is supplied with the variable direct control voltage, generated by the voltage-adjusting stage (15), as supply voltage for the CMOS inverter (14). The CMOS inverter (14) is operated, in dependence on the direct control voltage, below the knee-point voltage in its starting region in which the gain of the CMOS inverter (14) decreases, and additionally the dynamic output impedance of the CMOS inverter (14) increases, with decreasing direct control voltage.

Abstract: In an oscillator (1) comprising a parallel resonant circuit (4), which for fine-tuning the oscillator includes a variable capacitance which is variable in dependence upon a fine-tuning control signal and is constituted by the capacitance occurring in the collector circuit of a transistor. This transistor is a separate transistor (12) whose collector is capacitively coupled to the parallel resonant circuit and which is arranged in common base configuration for alternating current, while its operating point is chosen to be in its saturation range, the fine-tuning control signal being applied to the base-emitter path of this transistor and the transistor base-collector junction, which is in its pass region, being driven further into conduction by this signal within its control range on the one hand, and being driven from its pass region into its cut-off region on the other hand.

Abstract: A bridge circuit demodulator for frequency-modulated signals includes a parallel resonant circuit tuned to the carrier frequency of the FM signals. The resonant circuit includes the secondary winding of a transformer which is strongly coupled to the secondary winding. The signal to be demodulated is applied to the primary winding. Further, the signal to be demodulated is also applied to an LC phase shift circuit which shifts the signal applied to it through 90.degree.. The phase shift circuit has an output terminal connected to a center tap of the secondary winding and an input connected to receive the signal to be demodulated. The parallel resonant circuit and the phase shift circuit constitute the diagonals of the bridge circuit constituting the demodulator. The FM signal is applied to the phase shift circuit and to the parallel resonant circuit through separate outputs of a difference amplifier.

Abstract: In a self-oscillating mixing stage for FM radio receivers, comprising a transistor producing the oscillator signal and to whose emitter circuit the high-frequency signal is coupled and from whose collector circuit the intermediate-frequency signal is coupled out, the transistor being operated in the grounded-collector circuit mode to produce the oscillator signal and in the grounded-base circuit mode to process the high-frequency and intermediate-frequency signals.