| 摘要 |
<p>A power circuit for a low pressure sodium lamp utilises a high frequency oscillator which delivers a constant current to the lamp and which has a frequency of oscillation which is largely independent of variations in the impedance of the lamp. Sodium lamps have negative temperature-resistance coefficient, and the effect of the circuit is to counteract any tendency for the current taken by the lamp to increase as it heats up during operation. An additional inductance is provided between the oscillator itself and the lamp acts to stabilise the frequency of oscillation and hold constant the current delivered to the lamp.</p> |
