| 摘要 |
Unitary light sources comprise a compact HID lamp and an associated starting and operating circuit which can be operated at domestically available AC potentials. The HID lamp is loaded by incandescent filament devices which also provide the majority of the light generated during the HID warming-up period and also after power interruptions. The ballast incandescent filament and the input connections of a full-wave rectifier are connected in series via the light source input connections, while the HID lamp is connected across the rectifier output. A low-impedance-path device and a high-voltage pulse generator, which comprises a high-voltage electrode that is operatively connected to the HID lamp, are connected across the rectifier input. Initially, the voltage which is generated across the rectifier input is relatively high and the pulse generator and the low-impedance-path device react thereto in that they generate high-voltage pulses and also produce a low impedance path in series with the ballast incandescent filament in order to make the incandescent filament glow brightly. The high-voltage pulses generated, which are supplied to the high-voltage electrode, ionise the atmosphere inside the HID bulb. Once the HID lamp has started, the voltage generated across the rectifier input is no longer adequate to energise the low-impedance-path devices and the pulse generator devices. While the HID lamp is warming up, the brightness of the incandescent lamp ballast devices is reduced. A lamp operation maintenance circuit, which comprises a DC source, is connected across the output connections of the rectifier in order to supply lamp operating power during periods of rectifier conduction minima and in order to supply DC power as a lamp starting aid when necessary.
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