- A capacitor is a simple electronic component used to store an electric charge. Capacitors generally consist of two wide, flat sheets of metal called the conductors, separated by a thin insulating material, called the dielectric. Capacitors are used in nearly every type of electronic device including computers, lasers and radios.
- When a capacitor is hooked up to a power source, such as a battery, an electric charge flows into it. The part attached to the negative terminal is flooded with electrons, while the part attached to the positive terminal has electrons taken away from it, giving it a negative charge. The stronger the voltage, the more electricity the capacitor will store.
- At a given voltage, a capacitor will only store a certain amount of electricity. As it reaches saturation, the current flowing into the capacitor will slow and then stop. If the capacitor stays attached to this same current, nothing will change--no current will flow in or out of the capacitor. If the voltage drops, however, the capacitor will drain out. If the voltage attached to the terminals lowers enough, all of the electricity in the capacitor will flow back out.
- Capacitors have many different applications. One of the most important ones in DRAM, a type of memory used in computers. DRAM uses tiny capacitors to store bits--1's or 0's that form the basis of computer memory. A capacitor is charged up to stand for a 1 or discharged to stand for a 0. When the computer wants to know what value a particular bit has, it tests the capacitor to see if it contains a charge, then charges it up again. Capacitors are also used when quick bursts of energy are required. For example, some car audio systems use capacitors to give the amplifiers power when the system needs it.
