One, the definition of capacitance

Capacitance: It is the passive parts of an apparatus of a kind of impedance that allow a gender, it is one of electronic cell that use in great quantities in electronic equipment, apply extensively at lying between wave of straight, coupling, bypass, filter, harmonious loop, energy the respect such as changeover and control circuit. Represent electric capacity with C, capacitance unit has farad (F) , microfarad (farad of UF) , skin (PF) , 1F=10^6uF=10^12pF.

 

2, of capacitance name a method

The model of homebred capacitor is comprised by 4 parts commonly (unwell with) of capacitor of Yu Yamin, alterable, vacuum, ordinal represent name, material, classification and serial number respectively.

The first part: Name, express with the letter, capacitor uses C.

The 2nd part: Material, express with the letter.

The 3rd part: Classification, express with the number commonly, express with the letter individually.

 

The 4th part: Serial number, express with the number. Represent the material of the product with the letter: A- Tantalum electroanalysises, B- aluminium of the blame polarity film such as polystyrene, C- high frequency pottery and porcelain, D- electroanalysises, E- other material electroanalysises, G- alloy electroanalysises, glair of glass of H- compound medium, I- , J- the polarity such as dacron of metalized paper, L- niobium of organic film, N- electroanalysises, O- glass film

 

3, the classification of capacitor

1, divide kinds big according to the structure: Secure capacitor, alterable capacitor and fine tuning capacitor.

2, by electrolyte classification has: Organic medium capacitor, inorganic medium capacitor, electroanalysis capacitor and air medium capacitance.

3, by utility cent has: Wave of high frequency bypass, low frequency bypass, filter, harmonious, high frequency coupling and low frequency coupling.
 

 

Commonly used capacitance is classified

 

4, commonly used capacitor

 

Aluminium electroanalysises capacitance
 

1, aluminium electroanalysises the waterleaf paper mix that capacitor has mushy electrolyte with dip is among two aluminum foil winding and into, change oxidation film thinly to make the capacitor of medium. Because oxidation film has quality of only guide cable, electroanalysis so capacitor has polarity, capacity big, ability gets error of big pulsatile electric current, capacity big and leak electric current is big wait for character; Common unwell at be in high frequency issue application with microtherm, unfavorable use in wave of filter of coupling of bypass of low frequency of 25kHz above frequency, signal, power source.

 

Capacitance: 0.47- – 10000u

Rated voltage: 6.3- – 450V

Main characteristic: Volume is minor, the size is large, loss is big, leakage of electricity is big

Application: Wave of power source filter, low frequency coupling, go Ou, bypass

 

Tantalum capacitance
 

2, tantalum electroanalysises capacitor (CA) niobium electroanalysises capacitance (the Tantalum that CN) uses agglomeration piece make positive electrode, character of temperature of manganese dioxide of electrolyte use solid, frequency character and dependability all excel general electrify solves capacitor, especially leakage current is dinky, sex of keep in storage is good, life is long, capacity error is small, and volume is minor, can get the oldest capacitance voltage product is opposite below unit volume of pulsatile electric current be able to bear or endure get ability difference, in if attaint assumes short circuit position easily,exceeding small-sized tall reliable parts.

Capacitance: 0.1- – 1000u

Rated voltage: 6.3- – 125V

Main characteristic: Loss, leakage of electricity is less than aluminium to electroanalysis capacitance

Application: Aluminium is replaced to electroanalysis in the circuit with high demand capacitance

 

Filmy capacitance

 

3, film capacitor

Structure and paper capacitor are similar, but with get together it is good that the material of small loss model such as fat, polystyrene makes medium frequency character, interpose report loss is small cannot the size with large make it, heat-resisting ability differs filter, integral, oscillation, time circuit.

 

A polyester (polyester fibber) capacitance (CL)

Capacitance: 40p- – 4u

Rated voltage: 63- – 630V

Main characteristic: Minor volume, high capacity, heat-resisting is able to bear or endure wet, stability is poor

Application: Not tall to stability and loss requirement low frequency circuit

 

B polystyrene capacitance (CB)

Capacitance: 10p- – 1u

Rated voltage: 100V- – 30KV

Main characteristic: Stable, small loss, volume is larger

Application: Taller to stability and loss requirement circuit

 

C polypropylene capacitance (CBB)

Capacitance: 1000p- – 10u

Rated voltage: 63- – 2000V

Main characteristic: Function and get together benzene is similar but volume is minor, stability is differred slightly

Application: Replace much to get together benzene or micaceous capacitance, use at the requirement taller circuit

 

Ceramics capacitance

 

4, porcelain interpose capacitor

Wear heart type or raise capacitor of interpose of pillar structure porcelain, its electrode installs screw namely. Down-lead inductance is dinky, frequency character is good, interpose report loss is small, temperature compensates action cannot the size with large make it, suffer oscillatory meeting to cause a capacity change is particularly comfortable at high frequency bypass.

 

Capacitance of interpose of A high frequency porcelain (CC)

Capacitance: 1- – 6800p

Rated voltage: 63- – 500V

Main characteristic: High frequency loss is small, stability is good

Application: High frequency circuit

 

Capacitance of interpose of porcelain of B low frequency (CT)

Capacitance: 10p- – 4.7u

Rated voltage: 50V- – 100V

Main characteristic: Volume is minor, valence cheap, loss is big, stability is poor

Application: The low frequency circuit with not high demand

 

5, alone stone capacitor (multilayer capacitor of pottery and porcelain) be in a certain number of piece the coverture on base of film of pottery and porcelain with electrode paddle material, superposition hind is circled form cannot intersected whole, reoccupy colophony covers outside and lean into minor volume, high capacity, Gao Ke and high temperature resistant new-style capacitor, the low frequency of tall dielectric constant alone stone capacitor also has stable property, bulk is dinky, error of Q value tall size is bigger noise bypass, filter, integral, oscillating circuit.

 

Capacity limits: 0.5PF- – 1UF

Compression: Duple and rated voltage.

Main characteristic: Capacitance big, bulk tall, capacitance stabilizes small, dependability, high temperature resistant be able to bear or endure wet sex is good etc.

Use range: Apply extensively at electronic nicety instrument, all sorts of small-sized electron equipment make wave of syntonic, coupling, filter, bypass.

 

5, parameter of capacitor major attribute

 

1, nominal capacitance and tolerance

 

Nominal capacitance is a mark the capacitance on capacitor.

 

Capacitor is actual capacitance and nominal the deviation of capacitance weighs an error, precision says in permission deviation range. Accuracy class and allow error correspondence to concern: 00(01)-±1% , 0(02)-±2% , I-±5% , II-±10% , III-±20% , IV-(+20%-10%) , V-(+50%-20%) , VI-(+50%-30% )

 

General capacitor is commonly used class of I, II, III, electroanalysis capacitor uses level of IV, V, VI, choose according to utility.

 

2, rated voltage leaves the virtual value of highest volts d.c. that can be increased in capacitor continuously in lowermost environment temperature and rated environment temperature, tag directly commonly go up in capacitor crust, if working voltage exceeds the compression of capacitor, capacitor puncture, cause not repairable permanent damage.

 

3, insulation resistance

Volts d.c. is added on capacitance, generate residual current, both than calling insulation resistance. When capacitance is lesser, basically depend on the exterior condition of capacitance, when the capacity is more than 0.1uf, basically depend on the function of medium, insulation resistance has been jumped over greatly more. The time of capacitance is invariable: Introduced time constant for the insulation circumstance of capacitance of appropriate evaluation high capacity, he is equal to the product of the insulation resistance of capacitance and capacity.

 

4, loss capacitance falls in electric field action, the energy that in unit time internal cause calorific place wastes is called loss. Of all kinds capacitance stipulated its allow a value in the loss inside some frequency limits, the loss of capacitance is main by dielectric loss, the resistor place of all metal part causes conductance loss and capacitance. Below the action of dc field, the loss of capacitor guides with leaking the form of loss exists, general and lesser, handing in change below the action of electric field, the loss of capacitance guides with leakage not only about, and build a process to concern with periodic polarization.

 

5, frequency is characteristic

As the rise of frequency, the capacitance of general capacitor presents the law that drop.

 

6, capacitor capacity is indicative

1, straight mark law

With number and unit symbol direct line out. If 01uF represents 0.01 small ways, some capacitance use “R” to express

 

Show decimally, if R56 represents 0.56 small ways.

 

2, literal symbol law

The combination that has the law with number and article character date will represent a capacity. If P10 expresses 0.1pF, 1p0 expresses

 

1pF, 6P8 expresses 6.8pF, 2u2 expresses 2.2uF

 

3, color patch law

Coloring annulus or lubricious dot express the main parameter of capacitor. The color patch law of capacitor and resistor are identical. Symbol of capacitor deviation mark: + 100%-0- – H, + 100%-10%- – R, + 50%-10%- – T, + 30%-10%- – Q, + 50%-20%- – S, + 80%-20%- – Z.