High voltage capacitors are passive electronic components that store charge and energy for use in high voltage applications. They consist of two conducting plates separated by an insulating material called the dielectric. Film capacitors are high voltage capacitors made out of plastic. There are two basic types:
Air variable capacitors are used to tune L-C resonant circuits found in radio frequency power amplifiers. They are also found in antenna impedance matching networks. Their simple design offers high voltage ratings, low leakage and a high quality factor (Q). Air variable capacitors are non-polarized.
This means that a capacitor must be physically large to possess a large value of capacitance. Another important factor is the voltage rating of a capacitor. The dielectric strength limits the maximum voltage that can be applied to a material before it breaks down.
Another important factor is the voltage rating of a capacitor. The dielectric strength limits the maximum voltage that can be applied to a material before it breaks down. When a material (for example, an insulator or dielectric) experiences voltage breakdown, it loses its insulator and dielectric properties and starts acting like a conductor.
The applications of air capacitors include the following. This capacitor is normally used in resonant, LC circuits, which need changes within capacitance. These circuits comprise radio tuners, frequency mixers & impedance matching components for antenna tuners.
Air capacitors have a small capacitance value that ranges from 100 pF – 1 nF whereas the operating voltage ranges from 10 to 1000V. The breakdown voltage of dielectric is less so electrical breakdown will change within capacitor so this can lead to the defective working of air capacitor.