Generally speaking, traditional incandescent bulbs work by running electrical current through a filament, using the filament's high temperature to generate continuous spectrum radiation. As a result, incandescent bulbs are incredibly inefficient. Only about 15 % of the energy they consume generates light. The rest is wasted as heat.
一般說來，傳統的鎢絲白熾燈，發光原理是讓電流通過燈絲線圈，高溫發熱後產生連續性光譜的電磁波輻射，因此白熾燈的電能中有很大部分都是熱能，只有 15 % 發光，效率很低。