Abstract: Hybrid circuits are usually secured with contact pins (combs) on printed circuit boards by undergoing a flow solder bath. Further, surface-mountable components are soldered on the printed circuit board in a furnace. Two soldering processes are necessary for this purpose. The method of the invention avoids one of the soldering processes by applying through-contacted bores on the carrier substrate of the hybrid circuit. These through-contacted bores are put in place onto solder surfaces of the printed circuit board having a paste solder and the overall arrangement is soldered in a furnace.

Abstract: The invention concerns the distribution of electric power to several functional units (10, 11, 12) with variable power consumption. A preset limit value (Pmax) of the total power supply which is lower than the sum of the highest possible individual powers (P10, P11, P12) is maintained. By evaluating the total power consumption (I) or the operating voltage (U) of all functional units (10, 11, 12), an increase in the supply current or a drop in operating voltage (U) is used to reduce the supply current (I3) of functional units(12) of a lower importance is favor of the supply current of functional units (11) of a higher importance. This invention is used especially in electrical telephone subscriber's stations that are supplied over the subscriber's line.

Abstract: A circuit arrangement for the control of the series switching element of a clocked power supply unit has a pulse signal (Vt) delivered by a pulse generator. The pulse-interval ratio of the pulse signal can be varied as a function of a regulating signal (Vc) derived from the output side of the power supply unit and delivered by way of an optoisolator (13). The portion of the circuit employed as pulse generator (1) includes an operational amplifier (10) with feedback at both inputs. One feedback branch of the amplifier (10) contains at the amplifier input a capacitance (15) and a variable resistance. The variable resistance is formed by the parallel connection of a phototransistor (132) of an optoisolator (13) and an ohmic resistor (12). Accordingly, it becomes possible to produce a variation of the pulse-interval ratio of the pulse signal (Vt) either solely by modification of the pulse length or solely by modification of the pulse intervals.

Abstract: A receiving level control signal is generated line side, and the data signal is reproduced line side of a receiving circuit for signal transmission systems to regenerate a data signal and to generate a receiving level control signal from a received bipolar input signal, in which line and operating side are electrically isolated.

Abstract: In a signal transmission system whose transmission line (16) is connected to a line side component (66, 68) of a respective transmitter (12) and receiver (14) and is electrically isolated from the operating side, the line side component (66, 68) of the respective transmitter (12) and receiver (14) is powered from the operating side over through an isolating DC/DC-transducer (10).

Abstract: In an output circuit for a signal transmission system to generate a bipolar output signal, a power output stage (62) is driven by a data signal and a transmitter release signal via an isolation stage (18) and a logic network (64). The power output stage comprises two complementary transistors whose bases are each separately driven from an output (50, 56) of the logic network (64) so that only one of the two transistors (54, 60) is switched to conducting in the presence of a transmitter release signal corresponding to the polarity of the output signal to be produced and so that both transistors (54, 60) are closed, independent of the data signal, in the absence of a transmitter release signal.