For a layman, there seems to be no difference between a plasma and LCD TV. Both provide high-resolution, high-contrast images and both are flat, sleek and can be mounted on a wall. The difference lies in the technology that drives them.

Plasma TVs work with inert gases like xenon or neon, which are excited by electric pulses from specialized cells called pixels. This makes the gases glow. These glowing gases, in turn, produce the correct blend of red, blue and green light on the pixels. The pixels are illuminated by a fluorescent light bulb, which is driven by semiconductor software on the motherboard.

LCDs are actually thin film transistors (TFT), which contain liquid filled crystals between two plates of glass. LCDs work by blocking out unwanted light. When the signal hits the TFTs, they contort to a required angle, thus allowing only the requisite amount of light to pass through. A lamp behind the screen or a thin LCD bulb provides illumination to the TFT.

LCD TVs and plasma TVs have their individual strengths and weaknesses. Plasma TVs show better contrasts. Contrast means the ratio between the blackest black and the whitest white. A plasma TV can produce contrasts of even 3000 to 1, which is very high by LCD standards. LCD TVs can provide contrasts up to 900 to 1. However, in LCD technology, even a low contrast ratio can produce much better images.

Plasma TVs produce colors by addition of red, blue and green while LCD TVs produce colors by blocking unwanted light from the spectrum. Hence, plasma TVs produce colors by additive principle, while LCD TVs do the same by subtractive principle. That's why plasma TVs are much better at producing colors than LCD TVs.

Plasma TVs also have wide viewing angles, as much as 160 degrees. Since LCD TVs produce images by an LCD lamp behind the screen, viewing angles aren't wide. LCD TVs produce differently colored images when viewed at higher horizontal angles.

Though plasma technology wins over LCD technology in color, contrast and brightness, LCD wins hands down when it comes to the functionality. LCD TVs have greater longevity. Most LCD TVs can last up to twice the lifetime of a plasma TV. LCD TVs are also better suited to usage at higher altitudes or while traveling, because LCD technology does not use any gases, and is not subjected to air pressure.

LCD TVs are also energy efficient, as they require less voltage. This helps in reducing electricity bills.

Earlier LCD TVs were priced much higher than plasma TVs. But due to stiff competition, their prices have come down drastically. According to their current standing, LCD TVs cost only marginally more than plasma TVs.