CapacitorFebruary 9, 2017
Active VolcanoesFebruary 10, 2017
There are different types of capacitor and each of the different types of capacitors has its own performance parameters and can be used in different applications. But they all conform to the same basic physical laws. This determines the basic way the capacitor operates.All capacitors work in essentially the same way, key differences in the construction makes an enormous difference in their properties.
Dielectrics and Capacitors
The main element of the capacitor that gives rise to different properties is the DIELECTRICS . These Dielectrics are filled inside the capacitor.Typically the different types of capacitor are named after the type of dielectrics they contain. It’s dielectric constant will alter the level of capacitance that can be achieved .
Different Types of Capacitors
Ceramic capacitor are most commonly used type of capacitor .Since being cheap and reliable it is widely used. Their loss factor is particularly low although this is dependent on the exact dielectric that is in use. This is used in many applications such as audio amplifiers.
Electrolytic capacitors are a type of capacitor that is polarised. They are able to offer high capacitance values.They are most widely used for low frequency applications – power supplies, decoupling and audio coupling applications .
Silver Mica Capacitor
Silver mica capacitors are not widely used these days, however they offer very high levels of stability, low loss and accuracy where space is not an issue. They are primarily used for RF applications like transmission and reception of signals.
Polyester Film Capacitor
Polyester film capacitors are used where cost is a consideration as they do not offer a high tolerance. Many polyester film capacitors have a tolerance of 5% to 10%, which is adequate for many applications. They are generally available in leading electronics component.
The polycarbonate capacitors has been used in applications where reliability and performance are critical. The polycarbonate film is very stable and enables high tolerance capacitors to be made which will hold their capacitance value over time. In addition they have a low dissipation factor, and they remain stable over a wide temperature range, many being specified from -55°C to +125°C. However the manufacture of polycarbonate dielectric has ceased and their production is now very limited.
The polypropylene capacitor is sometimes used when a higher tolerance type of capacitor is necessary than polyester capacitors offer. As the name implies, this capacitor uses a polypropylene film for the dielectric. One of the advantages of the capacitor is that there is very little change of capacitance with time and voltage applied.
This capacitor type uses glass as dielectric material.It is expensive however these capacitors offer very high levels or performance in terms of extremely low loss, high RF current capability and with negligible piezo-electric noise .
Super Capacitors are also called as Ultra Capacitors.These capacitors have very large values of capacitance, of up to several thousand Farads. They find uses for providing a memory hold-up supply and also within automotive applications.