Cell phones are an extremely common tool in today's technologically advanced world. Cheap, portable, and effective, these small phones are considered by some to be a necessity. However, a cellular phone is not actually a real phone in the true sense. A cell phone is in fact a radio transmitter and receiver. When a person speaks into a cell phone, the machine translates their speech into radio waves. These waves are relayed through cell phone towers and delivered to another phone. Similarly, when a cell phone receives a call, it transfers the radio frequency back into speech. This is the reason that being underground, or in a concrete building, can make cell phone reception difficult.
The applicable term for radio waves, and at what power they're at, is calling radio frequency energy. Cell phones don't have a great deal of radio frequency energy, or RF. Generally speaking a cell phone has a radio frequency energy of somewhere between 850 and 1900 Megahertz. Put in practical terms, that is somewhere between a portable radio and a microwave oven. All in all, a cellular phone is a relatively weak device. However, there is still a question as to whether or not the waves it produces have more of an effect that people think.
Effects on Users
People who use cell phones are exposed to all of the radio frequency energy that they create. Large amounts of RF can cause body tissue to heat up, and to overheat connected tissues. This is counteracted by the body naturally, since blood will absorb heat and transfer it away from a tissue. Regardless, the RF generated by a cell phone isn't enough to cause tissue to heat anyway since the energy is so relatively small.