摘要:
A process and circuit for striking a high-pressure gas discharge lamp in which, in order to reduce the stress on the lamp and the power required, striking pulses are alternately applied to the lamp only during an initial period and the striking process is temporarily interrupted during a second, longer, period.
摘要:
Ein Elektronisches Vorschaltgerät zum Betrieb einer Niederdruck-Entladungslampe (LA), enthält einen in seiner Ausgangsfrequenz variierbaren Wechselrichter (S1, S2), eine Gleichrichterschaltung (1), die den Wechselrichter (S1, S2) speist, und einen Lastkreis, der mindestens einen Reihenschwingkreis (L1, C1) und mindestens eine Gasentladungslampe (LA) enthält und der von dem Wechselrichter (S1, S2) mit einer variierbaren Wechselspannung gespeist wird. Um das Entstehen von Oberwellen zu vermeiden, ist zwischen dem Ausgang der Gleichrichterschaltung (1) und dem Eingang des Wechselrichters (S1, S2) eine Reihenschaltung aus zwei Dioden (D1, D2) und einer dazwischenliegenden Pumpdrossel (L B ) sowie ein parallel zum Eingang des Wechselrichters (S1, S2) liegender Speicherkondensator (C B ) angeordnet und der Lastkreis wird mit dem wechselspannungsgenerator-seitigen Ende der Pumpdrossel (L B ) über einen Rückkopplungskondensator (C C ) verbunden.
摘要:
An electronic ballast for a low-pressure discharge lamp (LA) contains an inverter, which is supplied with direct voltage (UBUS) and whose output is connected to a load circuit containing connecting contacts for the lamp (LA). Said ballast also contains a filament transformer, which has a primary winding (Tp) that is connected to the output of the inverter, and a secondary winding (Ts1, Ts2) for heating each of two electrodes of the lamp (LA) respectively, said secondary winding being located in a heating circuit with a filament (W1, W2). Finally, the ballast has a series circuit that lies parallel to the load circuit. Said series circuit contains the primary winding (Tp) of the filament transformer and an electronic switching device (S3, S4). The currents are measured and evaluated in one of the two heating circuits and in the primary winding (Tp) of the filament transformer in order to determine the lamp type and the lamp mode.
摘要:
A process and circuit for striking a high-pressure gas discharge lamp in which, in order to reduce the stress on the lamp and the power required, striking pulses are alternately applied to the lamp only during an initial period and the striking process is temporarily interrupted during a second, longer, period.
摘要:
Es ist ein Vorschaltgerät für mindestens eine Gasentladungslampe mit einem Wechselrichter, der zwei in Serie liegende an eine Gleichspannungsquelle angeschlossene und im Gegentakt geschaltete Schalter (S1, S2) aufweist und einem zu einem der beiden Schalter (S1, S2) parallel geschalteten Lastkreis, der einen Serienresonanzkreis (L1, C1) und die Lampe (LA) enthält, vorgesehen. Zusätzlich ist ein ebenfalls an den Wechselrichter angeschlossenen Heizkreis (T, S3, R1) zur Stromversorgung der Lampenwendeln vorgesehen, der einen weiteren periodisch schaltbaren Schalter (S3) zur Steuerung des Heizstromes enthält, wobei der Heizkreis ebenfalls zu einem der beiden Schalter des Wechselrichters parallel geschaltet ist.
摘要:
In electronic ballasts for gas discharge lamps (3) which consist of a bridge rectifier (1) to be connected to the a.c. mains and a converter (2) connected downstream thereof, the brightness of the lamp may flicker, which is particularly annoying with the lamp (3) dimmed. To prevent this flicker, it is opposed that the operating potential terminal (mass) (6) inside the circuit be connected in the a.c. manner to the protective earth (S) of the a.c. mains. A second method may consist in connecting the internal reference potential terminal (mass) (6) to the phase terminal (L) and/or the neutral terminal (N) or with one or both of input terminals (10, 11) of the bridge rectifier (1) in the a.c. manner. In a third method, the a.c. 'hot' output terminal of the bridge rectifier (1), which is connected to the internal reference potential terminal (mass) (6) via a smoothing capacitor (C4), is to be connected in the a.c. manner to the protective earth (S) of the a.c. mains. Yet another method is to screen the lines (15-18) leading to the lamp (3) and to connect the screens (15, 16, 17, 18) to the circuit-internal reference potential terminal (mass) (6).
摘要:
A fluorescent lamp ballast for pulsed-mode operation and the use of a self-excited or externally controlled half or full bridge circuit for the same purpose are disclosed. An electronic ballast of that type has a buffered direct voltage supply (Udc, udc) that may be drawn from the effective power for the fluorescent lamp or lamps. The load circuit in which the fluorescent lamps are arranged has a choke (L1) connected in series, or if necessary a capacitor (C1) may be connected in parallel to the fluorescent lamp for starting purposes. Such a circuit should be designed in such a way that it allows the characteristic values of the fluorescent lamp light, i.e. its luminosity factor and colour temperature, to be modified without mechanically switching the choke. For that purpose, at least one electronic switching element (S1) or at least one pair of such switching elements (S1, S2, S3, S4) periodically supply the choke (L1) and the fluorescent lamp with voltage pulses (uac). The pairs of switching elements and the voltage pulses (uac) may be frequency-modulated (f1, f2) by means of a control signal (f). This frequency-modulation may be ensured by gradual or continuously periodical frequency alternation (sinusoidally), so that the frequency is constantly modified and no disturbing or standing waves that could provoke an optical flickering are formed in the fluorescent lamp.