| 摘要 |
1285206 Supply circuits for discharge lamps AUCO NV 20 Oct 1969 [21 Oct 1968] 51310/69 Heading H2H A circuit for starting a discharge lamp includes a semiconductor switch to which gating pulses are applied through a breakdown device such as a diac. The other side of the device is connected to a capacitive voltage divider, and the arrangement is such that the starting operation is not repeated after the lamp has lit. In the circuit of Fig. 2, the lines A, B are connected through the lamp terminals to an A.C. source. The semiconductor switch is constituted by a triac 10 which is gated through a diac 11 by a voltage divider formed by a resistor 13 and capacitors 12, 14. A suppressor capacitor 8 and limiting choke 9 are also included. In other embodiments, Figs. 3 and 4 (not shown), further components are added to the voltage divider in order to cause the lamp to ignite gradually, and to cause a choke in series with the lamp to saturate on alternate halfcycles so that the filament current can be easily controlled. A parallel RC circuit in the voltage divider can be used to decrease the lamp intensity periodically. In another embodiment, Fig. 7 (not shown), the triac 10 is replaced by a thyristor in anti-parallel with a diode.
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