The amount of power a TV uses varies by the size and type of television. Plasma televisions use the highest consistent amount of power per square inch while microdisplays use the lowest. A 46-inch plasma has about 906 square inches of viewing space, which takes about .30 to .39 watts per square inch. Amps is equivalent to watts divided by volts, so 0.35(906)/120=2.6425 amps. A plasma TV uses 2.6425 amps.
A microdisplay rear projector television uses the least amount of power at 0.11 to 0.15 watts per square inch converting to 0.13(906)/120=0.9815 amps for a 46-inch microdisplay, or less than half of the amps used to run the plasma television. LEDs are purported to be even more efficient, at as little as one-fourth the power of a plasma television.
LCD televisions vary widely, using 0.16 to 0.41 watts per square inch, so a 46-inch LCD television could use as little as 1.208 amps or as much as 3.1 amps. Potentially more efficient, a traditional cathode-ray tube television uses 0.25 to 0.40 watts per square inch, which is a rate of 1.8875 to 3.02 amps for a 46-inch television.
The most energy-efficient television with the least current is the microdisplay. Plasmas and LCDs run double to triple the energy consumption and current running through them.