Overview of Capacitor technology

Capacitors (and inductors) have the ability to store electrical energy, inductors store energy as a magnetic field around the component, but the capacitor stores electrical energy directly, as an ELECTROSTATIC FIELD created between two metal "plates".

Basic Circuit symbols for capacitors

• High Voltage Electrolytic- used in power supplies.

 • Axial Electrolytic; lower voltage smaller size for general purpose where large capacitance values are needed.

 • High Voltage disk ceramic; small size and capacitance value, excellent tolerance characteristics. 

• Metalised Polypropylene; small size for values up to around 2µF good reliability.

 • Sub miniature Multi layer ceramic chip (surface mount) capacitor. Relatively high         capacitance for size achieved by multiple layers, effectively several capacitors in parallel. 

Uses of Capacitors.

Decoupling--The most prevalent use of capacitors is to decouple a system,such as integrated circuit from sudden changes,including transfer of energy within the power supply.connecting a decoupling capacitor between supply voltage connection and ground in an integrated circuit,close to the IC itself helps maintain stable voltage lebel and supply fast power to the IC when needed.

Filtering-The second most common application of capacitor is in filtering to remove signals at unwanted frequencies.

Coupling-Because capacitors do not conduct DC currents, they are often used to separate different voltage level from each other by blocking DC voltages.

Timing and waveshaping-The manner in which capacitors charges and discharges through a resistor can be exploited for various timing purposes,such as introducing a delay or changing the shape of a waveform.

Oscillators-Together with inductive components,capacitors can be used to build oscillators for generating accurate sinusoidal signals.

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