A Plasma TV is a type of flat-panel television that creates images using thousands of tiny cells filled with plasma, or ionized gas. Each cell acts as a miniature fluorescent light, emitting red, green, or blue light when electrically charged. Plasma TVs were popular in the early 2000s for their vibrant colors, wide viewing angles, and ability to display deep blacks. However, they have largely been replaced by LED and OLED TVs due to improvements in energy efficiency, thinner designs, and longer lifespan.