When a television is operating, several different types of energy transformation are going on at the same time. Electrical signals head out from the base station into the set itself, and electricity converts into light, heat and sound energy. The law of conservation of energy says that energy can go from one form to another, but that it is impossible to create or destroy energy. The amount of energy inside the closed system that is the Earth is always the same. Some energy does convert to heat energy in most conversions, meaning that the television's electricity goes, at least in part, drifting off into the environment.
The conversion of electrical energy into other forms has always involved some risk, particularly with regard to heat energy. When heat energy does not have an escape, it can cause damage to internal components, even leading to the danger of fire. This is why most electronic devices feature a cooling fan or other mechanism for taking heat out of the internal cabinet. The internal components of the television use electricity to convert the signal coming in from the cable or through the wiring from the satellite dish or other device into light and sound, arranging the light into the predetermined patterns that show the viewer the program.