An electronic capacitor is usually a simple electrical component built into many circuit board designs that is capable of storing an electric charge for a period of time. Capacitors tend to be one of the larger elements on circuit boards, and often have a pancake-like shape or a cylindrical shape. Their interior is usually made up of two layers of conducting material separated by a central insulating layer.
Differences between the electronic capacitor and other electrical components like diodes or resisters are based on the fact that, instead of just regulating the flow of current, they can also block current until it reaches a certain level, amplify it, and restrict it. They also convert direct current (DC) to alternating current (AC). Variations on the electronic capacitor include the electrolytic capacitor converter or electrolytic condenser, which performs many of the same functions, but can use a gas or a partial vacuum as the insulating medium and a liquid electrolyte solution as one of the conducting plates.
Applications that call for the regulation of high current usually use electrolytic condensers instead of a standard electronic capacitor design because condensers achieve a larger capacitance level for the same volume of material and space used in the design. Capacitance is the rating of the ability to collect a electrical charge and is expressed as the ratio of the charge on one of a capacitor's conducting plates vs. the potential charge on the other plate. Charge capability is also related to the size of the electronic capacitor, so electrolytic condensers are usually much larger than standard capacitors.
The range of uses for the electronic capacitor is broad, and they are found in almost every digital and analog circuit. One of the main applications they have is as a form of voltage regulator that stores electrical energy like a battery and releases it in measured quantities. This makes them useful devices in audio systems to prevent amplifier overload, as noise filters in radio systems, and to regulate voltage in ignitions in automobiles. Their battery function also gives them widespread applications, from maintaining a trickle of current to computer memory when power is off to high voltage research in nuclear fusion, pulsed lasers, and as detonators in nuclear weapons. A capacitor's ability to block DC current and switch it to AC makes them useful voltage inverters in capacitance coupling applications that rely on analog circuitry, such as microphones, mechanical, and hydraulic pump systems.
Dangers posed by an electronic capacitor comes from its inherent ability to maintain an electrical charge for an extended time. They are often used to regulate the flow of current to one part of a circuit, and, when they fail, the circuit can burn out. They are also capable of delivering dangerous electric shocks to people due to the build-up of charge over time. As they age, the rating for the amount of charge they are made to hold deteriorates, so when charged to expected capacity, they can fail causing high-voltage discharges and even explosions.