摘要 |
A preheat-type fluorescent lamp, such as a negative glow discharge lamp, includes a cathode contained within an evelope and supported by a pair of lead-in wires. A thermal switch is located within the evelope shunting the cathode and electrically coupled to the supporting lead-in wires. Closure of the thermal switch during lamp operation produces a double hot spot on the shunted cathode. As a result, the cathode temperature is lowered sufficiently causing an improvement in the lumen maintenance and life of the lamp.
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