Older LCD TVs used cold cathode fluorescent lamps (CCFLs) to provide back lighting, whereas LED TV's used an array of smaller, more efficient light emitting diodes (LEDs) to illuminate the screen, which gave them a few advantages. Now, all LCD TVs use LED lights, and are colloquially considered LED TVs.

Flat screen LCD and plasma screens work in a completely different way.  In a plasma screen, each pixel is a tiny fluorescent lamp switched on or off electronically. In an LCD television, the pixels are switched on or off electronically using liquid crystals to rotate polarized light.

If you have an old tube TV like the one shown on the right, or a flat screen that does not have a built-in digital tuner (made before 2006, when digital tuners were mandated), you will need a digital TV converter box (also called a tuner box) in order to get free TV using an antenna.