My LED fixture

An LED is what's called a "solid-state lighting" technology, or SSL. Basically, instead of emitting light from a vacuum
(as in an incandescent bulb) or a gas (as in a CFL), an SSL emits light from a piece of solid matter.
 In the case of a traditional LED, that piece of matter is a semiconductor.

Stated very simply, an LED produces light when electrons move around within its semiconductor structure.

In the beginning Mark new holes Drill out new holes & notch
out slot for Lt socket