Available capacitor types, very small precision trimming used in oscillator or radio circuitslarge power metal box type used in high voltage power correction and softening circuits from capacitorsit varies up to capacitors.
DifferentComparisons between capacitor types are usually made in relation to dielectric used between plates.Variable type that allows us to change capacitance values for use in radio or "frequency adjustment" type circuits, such as resistorsthere is also a capacitor.
Commercial typeCapacitors are made of metallic foil, which must be passed through thin layers of either paraffin-impregnated paper or Mylar as dielectric material.Somecapacitors look like tubes, this is because the metal foil plates are wrapped in a cylinder to form a small package compressed with dielectric material that insulates between them.
Smallcapacitors are usually made of ceramic materials and then immersed in an epoxy resin to close them.Either way,capacitors play an important role in electronic circuits, so what is available here is more "common"We will share with you a few of the types of capacitors.
Dielectriccapacitors are usually of variable type and a continuous capacitance variation is required to adjust transmitters, receivers and transistor radios.Variable dielectric capacitors are multi-plate air gap types with a series of fixed plates (stator blades) and a series of moving plates (rotor blades) moving between fixed plates.
The position of the moving plates according to the fixed plates determines the total capacitance value.Capacitance is usually at its maximum when the two sets of plates are completely intertwined.High voltage type settingcapacitors have air gaps with relatively large gaps between plates or fault voltages reaching thousands of volts.
In addition to continuously variable types, preset type variable capacitors called Trimmers are also available.These are usually small devices that can be adjusted or "pre-adjusted" to a certain capacitance value with the help of a small screwdriver, and are available in very small capacitances of 500pF or lower and are not polarized.
Film Type Capacitor
Moviecapacitors are the most commonly found among all types of capacitors, consisting of a relatively large family of capacitors with a difference in dielectric properties.These include polyester (Mylar), polystyrene, polypropylene, polycarbonate, metallized paper, Teflon, etc. Movie typecapacitors, realavailable in capacitance ranges as small as 5pF to 100uF depending on the type and voltage of the capacitor.Moviecapacitors also have a variety of shapes and case styles, including:
- Winding and Filling (Oval and Round) – where the capacitor is wrapped with a tight plastic tape and filled with epoxy to seal the ends.
- Epoxy Case (Rectangular and Round) – where the capacitor is placed in a molded plastic shell and then filled with epoxy.
- Metal Hermetically Sealed (Rectangular and Round) – where the capacitor is placed in a metal tube or box and closed again with epoxy.
Film Capacitors that use polystyrene, polycarbonate or Teflon dielectrically are sometimes referred to as "Plastic capacitors".Structure of plastic film capacitors, paper filmsimilar to that of their capacitors, but use a plastic film instead of paper.Plastic film compared to impregnated paper typesThe main advantage of capacitors is that they work well in high temperature conditions, have smaller tolerances, have a very long service life and high reliability.Movieexamples of capacitors are rectangular metallized film and cylindrical film and foil types, as shown below.
Radial Tip Type
Axial Tip Type
Film and foil type capacitors are made of long thin strips of thin metal foil, together with dielectric material wrapped in a tight roll and then sealed in paper or metal tubes.
These types of films require a much thicker dielectric film to reduce the risk of tearing or puncturing the film, and therefore are more suitable for lower capacitance values and larger case sizes.
Metallized foil capacitors have metallized conductive film that is sprayed directly on both sides of dielectric, which gives the capacitor self-healing properties and therefore can use much thinner dielectric films.This allows higher capacitance values and smaller case sizes for a specific capacitance.Film and foil capacitors are often used for higher power and more precise applications.
Ceramic Capacitors or DiscsCapacitors, sometimes orange and lentil legumes-like capacitors are referred to as "Lentil Capacitors". As they are called, it is made by lining both sides of a small porcelain or ceramic disc with silver, and then stacked to form a capacitor.For very low capacitance values, a single ceramic disc of approximately 3-6 mm is used.Ceramiccapacitors have a high dielectric constant (High-K) and are used to achieve relatively high capacitances of a small physical size.
They exhibit large nonlinear changes in capacitance against temperature and are ultimately used as de-coupling or bypass capacitors because they are non-polarized devices.Ceramiccapacitors have values ranging from several picophageds to one or two microfarads (μF), but their voltage values are usually quite low.
CeramicCapacitor types usually have a 3-digit code in their bodies to define capacitance values in pico-farads.Usually the first two digitsindicates the capacitor value, the number of zeros to add to the third digit.For example, a ceramic disc marked 103the capacitor will show 10 and 3 zeros on picos-farads equivalent to 10,000 pF or 10nF.
Similarly, the numbers 104 indicate 10 and 4 zeros in pica-farads , equivalent to 100,000 pF or 100nF, and so on.Therefore, in the picture on the ceramic capacitor, the numbers 154 indicate 15 and 4 zeros in pica-farads, which are equivalent to 150,000 pF or 150nF or 0.15μF.Letter codes are sometimes used to indicate tolerance values: J = 5%, K = 10%, or M = 20%, and so on.
Electrolytic capacitors are usually used when very large capacitance values are required.Here, instead of using a very thin layer of metallic film for one of the electrodes, a semi-liquid electrolyte solution in the form of jelly or paste, which acts as the second electrode (usually the cathode), is used.
Dielectric is a very thin layer of oxide that is electrochemically magnified in production with a film thickness of less than ten microns.This insulating layer is so thin that it is possible to make capacitors with a large capacitance value for a small physical size, since the distance between the plates d is very small.
Most types of electrolytic capacitors are polarized, that is, the DC voltage applied to capacitor terminals must be at the correct polarity, that is, positive to the positive terminal and negative to the terminal negative, because a false polarization will disrupt the insulating oxide layer.
All polarized electrolyticthe polarity of capacitors is clearly marked with a negative mark to indicate the negative terminal, and this polarity must be observed.
Electrolytic Capacitors are often used to help reduce surge voltage in DC power supply circuits due to their large capacitances and small dimensions, or for coupling and decupulation applications.Electrolytica main drawback of capacitors is their relatively low voltage values and electrolyticdue to the polarization of capacitors, they should not be used in AC welds.Electrolytics usually come in two basic form; Aluminum Electrolytic Capacitors and Tantalum Electrolytic Capacitors.
Aluminum Electrolytic Capacitors
Basically there are two types of Aluminum Electrolytic Capacitors, flat foil type and engraved foil type.The thickness and high refractive voltage of the aluminum oxide film give very high capacitance values according to these capacitor dimensions.
The foil plates of the capacitor are anodized by a DC current.This anodeing process adjusts the polarity of the plate material and determines which side of the plate is positive and which side is negative.
The type of engraved foil differs from the plain foil type, with aluminum oxide on the anode and cathode foils being chemically coated to increase the surface area and permeability.This is a size smaller than the equivalent value of a flat foil typegives capacitors, but has the disadvantage of not being able to withstand high DC currents compared to the flat type.In addition, tolerance intervals are quite wide up to 20%.An aluminum electrolyticTypical capacitance values for the capacitor are from 1uF to 47,000uF.
Engraved foil electrolytics are best used in coupling, DC blocking and bypass circuits, while flat foil types soften in power suppliesmore suitable as capacitors.But aluminum electrolytics are "polarized" devices, so reversing the voltage applied to the ends,the insulation layer inside the capacitorwith the capacitor, causing it to be destroyed.NeverthelessThe electrolyte used in the capacitor helps to heal a damaged plate if the damage is minor.
Since the electrolyte has the properties of self-healing of a damaged plate, foil also has the ability to re-anodize the plate.Since the anodized process can be reversed, the electrolyteAs will happen if the capacitor is connected with reverse polarity, it is capable of removing oxide coating from foil.Since the electrolyte is capable of transmitting electricity, if the aluminum oxide layer is removed or destroyed,by allowing the capacitor current to pass from one plate to anotherreflects the condenser in the form of flat wire.
Tantalum Electrolytic Capacitors
Tantalum electrolytic capacitors or tantalum beads are available in both wet (foil) and dry (solid) electrolytic types, the most common being dry or solid tantalum.Solid tantalum capacitors use manganese dioxide as their second terminal and equivalent aluminumphysically smaller than capacitors.
The dielectric properties of tantalum oxide are much better than aluminum oxide, which provides lower leakage currents and better capacitance stability; this makes them suitable for use in blocking, bypassing, separating, filtering, and scheduling applications.
Also, tantalum capacitors, although polarized, can tolerate binding to a reverse voltage much easier than aluminum types, but are rated at much lower operating voltages.Solid tantalum capacitors are usually used in circuits where the AC voltage is small compared to the DC voltage.
However, some types of tantalum capacitors include a combination of two capacitors that connect from negative to negative to create a "non-polarized" capacitor for use in low voltage AC circuits as a non-polarized device.In general, the positive tip is defined by a polarity mark on the body of the capacitor, the body of the tantalum bead capacitor has an oval geometric shape.Typical capacitance values range from 47nF to 470uF.
Electrolytic capacitors are widely used due to their low costs and small sizecapacitors, but electrolyticThere are three easy ways to destroy capacitors:
- Excessive voltage – excessive voltage causes the current to leak through dielectric, causing a short circuit state.
- Reverse Polarity – reverse voltage causes the oxide layer to self-destruct and malfunction.
- Extreme Temperature – excessive heat dries the electrolyte and shortens the life of the electrolytic capacitor.
In the next lesson about capacitors,We will look at some of the main features to show that there is more to the capacitor than just voltage and capacitance.