Capacitors generally come in a lot of sizes and types depending on what and where its going to done and its going to be fixed in a given circuit board (PCB) so this calls for the manufactures to build and construct capacitors of varies types and sizes with specific functions and materials as we are going to see in this article but before continuing further a capacitor type is determined by the material of the dielectric or the insulator separating the two adjacent plates of the capacitor so without saying more words lets jump straight in to the article and see all the possible types of capacitors used in electrical and electronic circuit designs and there specific functions on the circuit board. There are generally two types of capacitors just like resistors these are;
These like the fixed resistor have a constant capacitance and do not change at all in any point in time and its usually written and indicated on the body of the capacitor either in nano or micro faradays, faradays being the unit of measurement of capacitance, these capacitors include;
These are the commonest capacitors round and they are mostly orange and green in color with a ceramic dielectric and have a capacitance (ability to store charge) in the nano faradays (nF) range and they are commonly used due to their small size, high frequence handling and thy are not that expensive.
Like the name states the plates of these capacitors is separated by an electrolyte (dilute acid) which is generally sulphuric acid hance giving them the name electrolytic capacitors these are commonly useful because of their high capacitance values making then suitable for filtering AC ripples in power supplies.
These just like the ceramic capacitors but these have a much higher capacitance and have a film (thin plate) between the plates of the capacitor as a dielectric and this commonly used for high electronic and audio application some of the common examples include polyester, polypropylene etc
The mica capacitors have a glass like plate in between the two plates that this acts as the dielectric for the capacitor making them suitable for use in RF (Radio Frequence) and high frequence circuits since they are very stable and precise
These capacitors are very sensitive and made of dielectric material very a very high dielectric content and dielectric strength making them have a very high capacitance and very useful for backup power storage and energy storage applications in the electrical field
These are the capacitors that are made either by combining a lot of different capacitors internally to form a single capacitor and the capacitance is varied using a knob or the capacitor is made with a air gap since wen the space is between the plates is varied the capacitance changes and these capacitor include;
Trimmer capacitors are variable capacitors which serve the purpose of initial calibration of equipment during manufacturing or servicing. They are not intended for end-user interaction. Trimmer capacitors are almost always mounted directly on the PCB (Printed Circuit Board), so the user does not have access to them, and set during manufacturing using a small screwdriver. Due to their nature, trimmer capacitors are cheaper than full sized variable capacitors and rated for many fewer adjustments.
Air capacitors are capacitors which use air as their dielectric. The simplest air capacitors are made of two conductive plates separated by an air gap. Air capacitors can be made in a variable or fixed capacitance form. Fixed capacitance air capacitors are rarely used since there are many other types with superior characteristics
Inconclusion capacitors are mainly used for filtering frequences and removing of ripples and unwanted noise in the circuit and they come in different sizes and types to suit the circuit design and functionality of the board and some special capacitors like static capacitors are also used and connected in either star connection or delta connection to correct power factor issues in AC three phase Circuitry.
