Abstract: A monitoring device for monitoring an array (4) of electrical units, in particular an array of high capacity light emitting diodes (LEDs) (4.1-4.12). The electrical units are connected in series and driven by a constant electric current (I). The monitoring device has a bypass means (4.1a-4.12a) for each electrical unit (4.1-4.12), operable to bypass the respective electrical unit in case of a disconnection of the respective electrical unit, and an evaluation unit (3) connected in parallel with the array (4) of electrical units, said evaluation unit (3) being adapted to determine a total voltage (UT) of the array (4) of electrical units and to output a control signal (CS) indicative of a function status of the array (4) of electrical units in accordance with a value of the total voltage (UT) relative to a predetermined threshold value (VREF). Thus is provided an electric circuitry which allows an easy and reliable detection of a malfunction of the array of electrical units, e.g.

Abstract: An electrical relay circuit, comprising a load circuit with a series connection of a first generator (G1), a load component (R load) and a relay switch (S1) of a relay (RL1), wherein the relay switch (S1) has a closed position in which the load circuit is closed, and wherein the relay switch (S1) hat a magnetized position in which the load circuit is broken, further comprising an auxiliary circuit with a second generator (G2) for providing a control signal, wherein by means of the control signal the relay switch (S1) can be switched into the magnetised position, and wherein the auxiliary circuit keeps the relay switch (S1) in the magnetized position after the control signal is over, is characterized in that the first generator (G1) is connected to a series connection of the relay (RL1) and a constant current source (CCS) in both positions of the relay switch (S1), that the constant current source (CCS) is connected to an activation circuit (A) comprising the second generator (G2), wherein the constant current

Abstract: A method for operating a signal lamp (1), in particular a railway signal lamp, wherein the signal lamp (1) comprises as its illuminant at least one light emitting diode (=LED) (2), and wherein the luminous intensity of the signal lamp (1) is adapted to the brightness of the surrounding, is characterized in that the at least one LED (2) is operated during first time intervals as the illuminant of the signal lamp (1), and during second time intervals, the at least one LED (2) is operated as a photo diode, that first and second time intervals alternate over time, in particular periodically, and that the output voltage of the LED (2) during the second time intervals is used to control the operating current of the at least one LED (2) during first time intervals. The inventive method does without a separate sensor, thus allowing the use of a corresponding signal lamp arrangement which is simple and inexpensive.

Abstract: In a filter circuit (6) with a low-pass filter (7), the output of the low-pass filter (7) is regenerated over a reverse current diode (11) with the input of the low-pass filter or of a further low-pass filter (8) pre-connected to the low-pass filter (7). A circuit arrangement includes such a filter circuit (6) and a battery charger circuit (1) with a battery (2) and a d.c. generator (A).

Abstract: A method for operating a signal lamp (1), in particular a railway signal lamp, wherein the signal lamp (1) comprises as its illuminant at least one light emitting diode (=LED) (2), and wherein the luminous intensity of the signal lamp (1) is adapted to the brightness of the surrounding, is characterized in that the at least one LED (2) is operated during first time intervals as the illuminant of the signal lamp (1), and during second time intervals, the at least one LED (2) is operated as a photo diode, that first and second time intervals alternate over time, in particular periodically, and that the output voltage of the LED (2) during the second time intervals is used to control the operating current of the at least one LED (2) during first time intervals. The inventive method does without a separate sensor, thus allowing the use of a corresponding signal lamp arrangement which is simple and inexpensive.

Abstract: An electrical relay circuit, comprising a load circuit with a series connection of a first generator (G1), a load component (R load) and a relay switch (S1) of a relay (RL1), wherein the relay switch (S1) has a closed position in which the load circuit is closed, and wherein the relay switch (S1) hat a magnetized position in which the load circuit is broken, further comprising an auxiliary circuit with a second generator (G2) for providing a control signal, wherein by means of the control signal the relay switch (S1) can be switched into the magnetised position, and wherein the auxiliary circuit keeps the relay switch (S1) in the magnetized position after the control signal is over, is characterized in that the first generator (G1) is connected to a series connection of the relay (RL1) and a constant current source (CCS) in both positions of the relay switch (S1), that the constant current source (CCS) is connected to an activation circuit (A) comprising the second generator (G2), wherein the constant current

Abstract: A monitoring device for monitoring an array (4) of electrical units, in particular an array of high capacity light emitting diodes (LEDs) (4.1-4.12). The electrical units are connected in series and driven by a constant electric current (I). The monitoring device comprises: a bypass means (4.1a-4.12a) for each electrical unit (4.1-4.12), operable to bypass the respective electrical unit in case of a disconnection of the respective electrical unit, and an evaluation unit (3) connected in parallel with the array (4) of electrical units, said evaluation unit (3) being adapted to determine a total voltage (UT) of the array (4) of electrical units and to output a control signal (CS) indicative of a function status of the array (4) of electrical units in accordance with a value of the total voltage (UT) relative to a predetermined threshold value (VREF). Thus is provided an electric circuitry which allows an easy and reliable detection of a malfunction of the array of electrical units, e.g.

Abstract: In a filter circuit (6) with a low-pass filter (7), the output of the low-pass filter (7) is regenerated over a reverse current diode (11) with the input of the low-pass filter or of a further low-pass filter (8) pre-connected to the low-pass filter (7). A circuit arrangement includes such a filter circuit (6) and a battery charger circuit (1) with a battery (2) and a d.c. generator (A).