Cell phones basic operation is to emit a small amount of electromagnetic radiation. Generally cell phones emit signals via radio waves, which are comprised of radio-frequency (RF) energy, a form of electromagnetic radiation.
There’s a lot of talk in the news these days about whether or not cell phones emit enough radiation to cause adverse health effects. But the topic that has marked a concern is that cell phones are often placed close to or against the head during use, which puts the radiation in direct contact with the tissue in the head. There’s evidence supporting both sides of the argument.
When talking on a cell phone, a transmitter takes the sound of your voice and encodes it onto a continuous sine wave. A sine wave is just a type of continuously varying wave that radiates out from the antenna and fluctuates evenly through space. Sine waves are measured in terms of frequency, which is the number of times a wave oscillates up and down per second. Once the encoded sound has been placed on the sine wave, the transmitter sends the signal to the antenna, which then sends the signal out.
Cell phones have low-power transmitters in them. Most car phones have a transmitter power of 3 watts. A handheld cell phone operates on about 0.75 to 1 watt of power. The position of a transmitter inside a phone varies depending on the manufacturer, but it is usually in close proximity to the phone’s antenna. The radio waves that send the encoded signal are made up of electromagnetic radiation propagated by the antenna. The function of an antenna in any radio transmitter is to launch the radio waves into space; in the case of cell phones, these waves are picked up by a receiver in the cell-phone tower.
Electromagnetic radiation is made up of waves of electric and magnetic energy moving at the speed of light, according to the Federal Communications Commission (FCC). All electromagnetic energy falls somewhere on the electromagnetic spectrum, that ranges from an extremely low frequency (ELF) radiation to X-rays and gamma rays.
All cell phones emit some amount of electromagnetic radiation. Given the close proximity of the phone to the head, it is possible for the radiation to cause some sort of harm to the 118 million cell-phone users in the United States.
There are two types of electromagnetic radiation:
a) Ionizing radiation – This type of radiation contains enough electromagnetic energy to strip atoms and molecules from the tissue and alter chemical reactions in the body. Gamma rays and X-rays are two forms of ionizing radiation. These cause damage, which is why we wear a lead vest when X-rays are taken of our bodies.
b) Non-ionizing radiation – Non-ionizing radiation is typically safe. It causes some heating effect, but usually not enough to cause any type of long-term damage to tissue. Radio-frequency energy, visible light and microwave radiation are considered non-ionizing.