无极灯，也称无电极灯、感应灯。是一种没有电极和灯丝的照明设备，它通过灯管外的磁环产生电磁波激发灯管内的物质工作。例如低压气体无极灯内充填的是汞蒸气和稀有气体的混合气体，汞原子被电离、激发后释放出紫外线照射到灯管壁的荧光物质上，荧光物质发出可见光。虽然也填充了汞，但其固汞含量要低于荧光灯。其工作频率通常达到数百万赫兹，远高于普通的白炽灯和节能灯。由于省去了灯丝和电极，可以制成环形、螺旋形或管状等各种形状。其工作寿命可达近10万小时，工作效率也很高。

The internal electrodeless lamp or induction light is a gas discharge lamp in which the power required to generate light is transferred from outside the lamp envelope to the gas inside via an electric or magnetic field, in contrast with a typical gas discharge lamp that uses internal electrodes connected to the power supply by conductors that pass through the lamp envelope. There are three advantages to elimination of the internal electrodes: