Cell phones have made us a lot more connected. Now, there is no longer an excuse for not calling when we are going to be late. You can call a friend who is late for a rendezvous. You can call your spouse from the grocery store when you forget the ingredients in a recipe. It is hard to imagine how previous generations survived being so isolated.
Battery and Antenna
The battery and the antenna are the two parts of your cell phone you are most likely to encounter (and damage) if you open up your cell phone. The battery supplies the electricity that makes the phone work. Without the battery, nothing happens. The battery is protected as long as it is installed in the phone. If you take it out, it is surprisingly fragile and easy to drop. The antenna is the portal through which the phone is linked to other phones. In most phones it is a coil of wire attached to a removable cover that is easy to break.
Microphone and Speaker
The microphone and speaker are the channels through which the telephone communicates messages from other customers to you. The microphone you speak into converts sound to electricity. The speaker you listen to converts electricity into sound. When you speak into the microphone, your voice turns into electrical signals which get digitized and then transmitted out through the antenna. When the signal from another phone strikes your antenna, it first gets un-digitized, then sent to the speaker where it converts to sound.
Keyboard and LCD Screen
The keyboard and LCD form another pair of channels through which you communicate with the phone nonverbally. By pressing buttons on the keyboard, you issue data and commands to the phone--turn on, turn off, look up a number or call a number, among other things. The LCD screen is the way the phone communicates nonvocal data to you, including number dialed, last number called, who is currently calling you, etc. The keyboard and LCD screen not only handle nonverbal communications, but they also handle commands, errors and status reports.
The circuit board is the component of the phone that is most removed from direct interaction with you or with the outside world. It is also the part of the phone that controls how everything else works. It transforms digital signals to analog, and analog signals to digital. It also contains a miscellany of components that do not fit into the other categories. These include the buzzer and vibrator that alerts you to incoming calls, a SIM card that lets the cell phone tower know about your long-distance carrier, and a monitor to check the energy level of the battery so the phone can alert you when the battery needs charging.