Capacitor Types: electrolytic, ceramic, tantalum, plastic film

capacitors appear in all types of electronic equipment from computer-based equipment to radios televisions Wi-Fi routers cell phones in fact almost without exception any piece of electronic equipment will have many capacitors inside it big small fat thin cylindrical rectangular capacitors come in all shapes and sizes they also used different dielectrics and different methods of construction and this changes their performance it's important to understand the differences between the different types of capacitor because some work better in some areas than others in fact some won't work in some places at all where other types will so it's important to understand what the different types of capacitor are this is the circuit symbol for a capacitor in this case it is non polarized and here we see a polarized one a polarized capacitor must have any DC voltage across it in the right sense positive at one end and negative at the other the dielectric or the material between the two capacitor plates is very important it governs many of the capacitors properties things like capacitance levels voltage withstand temperature coefficient and many other things there are a number of types of capacitor that are more common than others and we're going to be taking a look at these possibly the most common of the aluminium electrolytic tantalum ceramic and finally plastic film capacitors beyond these there are several other types like silver mica glass super capacitors and some others but these aren't nearly so common so we won't be covering them in this video first up is the electrolytic capacitor this type normally comes in a metal can with an outer plastic sheath they come in a variety of sizes with a good range of values they're also available in both lead 'add and surface mount packages the markings on the capacitor are printed on the outer sheath in this first example it's possible to see the value itself and also the working voltage also very important is the mark for the negative terminal to ensure it's connected the right way round in the next example the value and voltage are given along with the temperature range and the maximum current the current rating is very important for applications like using power supplies where lots of current may be flowing let's summarize the main characteristics of the electrolytic capacitor first it is polarized having positive and negative terminals and it must be connected the right way round otherwise damage may result aluminium electrolytic snore Mele have large values of capacitance anywhere from about a micro farad right up to values of well I think the largest I've seen is around 47 thousand microfarads they typically have working voltage values up to figures of around 50 volts but some for use in high voltage supplies may be as high as 350 volts they have a high ripple current capability which makes them ideal for use in power supplies but on the downside they have a relatively high level of leakage and a poor value of Tolerance or accuracy often plus 50% and minus 20% which rules them out of precision applications and another limitation is their high frequency performance they're not normally used for frequencies much above 100 kilohertz and use with radio frequencies is definitely out another popular type of capacitor is the tantalum capacitor these capacitors are much smaller than electrolytic SAR seen here the lead adverse being in the form of a bead surface mount versions are also used a lot especially these days with mass production the markings on lead ones are generally in the form of figures these days although a color coding scheme was used some years ago markings are normally quite obvious being the value working voltage and a polarity indication for surface mount capacitors the value is generally marked in terms of the significant figures and a multiplier so in this instance the value is 47 times 10 to the power of 5 point-7 microfarads sometimes the values may be marked more directly and often the working voltage is added and of course the bar across one end indicates the positive terminal in summary the main characteristics of the tantalum capacitor are that it is polarized like the electrolytic requiring it to be fitted into the circuit in a particular way they have a high level of capacitance in a very small volume making them ideal for many of today's miniaturized pieces of electronic gadgetry they're only used in low voltage applications typically maximum working voltages available are around 35 volts or a little more unfortunately they have a low leakage level what they don't like is reverse voltages or / voltages they can explode if these are exceeded oh and they cannot take high ripple currents as well so they're not used for power supply smoothing ceramic capacitors form the mainstay of many designs the lead adverse have a number of slightly different formats but in most cases they're reasonably similar the surface mount versions are widely used in mass-produced equipment they're very cheap and easy to manufacture and are seen on almost every surface mount board markings are normally only seen on the lead adverse because the surface mount ones are normally too small we have a couple of examples of leader versions here this one shows the value and the voltage and this one shows not only the value in the working voltage but also the type of ceramic dielectric and the tolerance so to summarize the main characteristics of the ceramic capacitor include the fact that it is not polarized the values range from a few Pico farad's right up to around about probably 0.1 / microfarad the working voltage may be low for those designs using low voltages although values of a kilovolt or more are available for high voltage applications there are several different forms of ceramic dielectric that can be used these vary in their properties some enabling accurate tolerances to be quoted last others offer high capacitance levels for a given volume these capacitors are very successful and they're widely used in leading and surface-mount versions ceramic capacitors are also widely used for radio frequency or RF applications where they're able to provide excellent performance another type of capacitor that is widely used is the plastic film capacitor several different types of plastic film may be used each having slightly different characteristics names like polyester polystyrene and a host of other types are available in terms of their salient features these capacitors may use a metallized film or a plastic film with foil between the layers to form the plates the exact properties are dependent upon the type of film used values may range from around 100 pick farad's up to possibly even 10 microfarads they may have working voltages between 10 volts up to as much as 2 kilovolts generally these capacitors are used as leading devices although some surface mount versions are available but they're not as common as other types because there are issues with the high temperatures used for soldering surface mount components there we have it a whirlwind review of some of the major types of capacitor the electrolytic capacitor polarized and with high values but low tolerance and high leakage the tantalum which provides a large amount of capacitance in a small space but again polarized and it doesn't like any misuse the ceramic capacitor which is the workhorse of many designs and finally the plastic film capacitor with a variety of different types of film for the dielectric

Channel: ElectronicsNotes

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Keywords: capacitor types, types of capacitor, capacitors, electrolytic capacitor, aluminium electrolytic capacitor, tantalum capacitor, x7r, ceramic capacitor, c0g, plastic film capacitor, electronic circuits, electronic capacitor, surface mount capacitor leaded capacitor, different types of capacitor

Id: e3W0kdLodXo

Length: 8min 25sec (505 seconds)

Published: Tue Oct 11 2016