摘要 |
<p>High-intensity-discharge (HID) sodium lamp has a starting aid comprising a conducting ceramic which is hermetically sealed to and extends through an alumina arc tube at least at one end thereof to form an electrically conducting path. The conducting ceramic is fused to the alumina arc tube and is electrically conductive by virtue of having embedded therein a small percentage of finely divided refractory metal. At least during starting, the conducting ceramic is electrically connected through a resistor to the opposite lamp electrode and, as a result, on application of energizing potential, a glow discharge is established between an arc-tube-interior portion of the conducting ceramic and the adjacent electrode to ionize the atmosphere within the arc tube and facilitate lamp starting.</p> |