PrevNEXT

How Cell-phone Radiation Works

Source of Radiation

Radiation in cell phones is generated in the transmitter and emitted through the antenna.
Radiation in cell phones is generated in the transmitter and emitted through the antenna.

When talking on a cell phone, a transmitter takes the sound of your voice and encodes it onto a continuous sine wave (see How Radio Works to learn more about how sound is transmitted). 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.

Advertisement

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, which ranges from extremely low frequency (ELF) radiation to X-rays and gamma rays. Later, you will learn how these levels of radiation affect biological tissue.

When talking on a cell phone, most users place the phone against the head. In this position, there is a good chance that some of the radiation will be absorbed by human tissue. In the next section, we will look at why some scientists believe that cell phones are harmful, and you'll find out what effects these ubiquitous devices may have.

ElectronicsCell PhonesHow Cell Phones WorkElectronicsCell PhonesCan cell phones make you sterile?ElectronicsCell PhonesCell Phone PicturesElectronicsCell PhonesHow Cell Phone Jammers WorkElectronicsCell PhonesWhich cell phone should I buy for my grandmother?ElectronicsCell PhonesInside a Cell PhoneElectronicsTravel GadgetsIntroduction to Global Cell PhonesElectronicsCell PhonesHow are cell phones cloned?ElectronicsCell PhonesHow Prepaid Cell Phones WorkElectronicsCell PhonesCan you charge your cell phone with a fuel cell?ElectronicsCell PhonesTop 5 Future Cell PhonesElectronicsCell PhonesHow do I use my cell phone as a modem?ElectronicsCell PhonesIntroduction to How Video Conferencing Cell Phones WorkElectronicsCell Phones5 Ways to Donate Your Old Smartphone or Cell Phone to CharityElectronicsCell PhonesCell Phone Tower PicturesElectronicsCell PhonesHow Much Radiation Does Your Cell Phone Emit?ElectronicsHow-to TechHow to Unlock a Cell Phone or SmartphoneElectronicsCell PhonesCan extreme weather damage your cell phone?ElectronicsTravel GadgetsHow Wind-up Cell Phone Chargers WorkElectronicsCell PhonesHow to Tether a Cell PhoneElectronicsCell PhonesHow did digital technology change cell phone service?ElectronicsCell PhonesHow to Unlock an Android Cell PhoneElectronicsCell PhonesScientists Have Invented a Battery-free Cell PhoneElectronicsCell PhonesHow to Decide Between a Smart Phone and Cell PhoneElectronicsTelephone TechnologyHow to Forward Calls from a Landline to a Cell PhoneElectronicsCell PhonesHow to Import Pictures from a Cell Phone to a LaptopElectronicsTech's Effects on the Family5 Ways to Keep Your Kids Off Their Cell PhonesElectronicsTech for KidsCell Phones for Kids: When is the right time?ElectronicsCell PhonesWould a cell phone work on a submerged submarine?ElectronicsCell PhonesHow to Transfer Data from One Cell Phone to AnotherElectronicsCell PhonesCan you use a cell phone as a credit card?ElectronicsCell PhonesWhy is a cell phone called a cell phone?ElectronicsCell PhonesElectromagnetic InterferenceElectronicsCell PhonesWhat does GSM mean in a cell phone?ElectronicsCell PhonesHow does a vibrating cell phone or pager work?ElectronicsCell PhonesHow GPS Phones WorkElectronicsHow-to TechHow to Unlock GSM PhonesElectronicsCell PhonesHow Smartphones WorkElectronicsCell PhonesCell-phone CodesElectronicsCell PhonesCell-phone Frequencies - Cell phone FrequenciesElectronicsCell Phone AppsHow to Fake a GPS Location on Your PhoneElectronicsWirelessHow 5G WorksElectronicsTelephone TechnologyWhy does the phone still work when the electricity goes out?ElectronicsCell PhonesHow Cell-phone Radiation WorksElectronicsCell PhonesHow Cell-phone Viruses WorkElectronicsCell PhonesHow Cell-phone Implants WorkElectronicsHigh-Tech Gadgets5 Tips for Picking the Right SmartphoneElectronicsCell PhonesCell-phone Network Technologies: 3G - 3G Cell phonesElectronicsCell PhonesInside a Digital Cell PhoneElectronicsWirelessHow 4G WorksElectronicsCell PhonesDo Smartphones Really Charge Faster in Airplane Mode?ElectronicsCell Phones4 Reasons Your Phone Keeps Dropping CallsElectronicsCell PhonesPotential Health Risks - How Cell-phone Radiation WorksElectronicsCell PhonesSmartphone Hardware and Software - How Smartphones WorkElectronicsCell PhonesCell-phone Channels - Cell phone ChannelsElectronicsCell PhonesSource of Radiation - How Cell-phone Radiation WorksElectronicsCell PhonesCell Phone Jamming DeviceElectronicsCell PhonesAnalog Cell PhonesElectronicsFuture TechWhat Will Replace the Smartphone?ElectronicsWirelessHow WiFi Phones WorkElectronicsTelephone TechnologyDo smartphone covers really protect phones from damage?ElectronicsCell PhonesCell Phone Jamming Legal IssuesElectronicsCell PhonesCell Phone Network Technologies: 2G - 2G Cell phone NetworksElectronicsCell PhonesCell Phone Jamming BasicsElectronicsCell PhonesGSM and CDMA - How Cell Phones WorkElectronicsCell PhonesCould someone stalk you using your own smartphone?ElectronicsCell Phones6 Creative Uses for an Old SmartphoneElectronicsTravel GadgetsIntroduction to Global Cell Phones