We enter the world of the change holding a cost of capacitance of pottery and porcelain below.

 

One, voltage value greatened, capacitance is worth decrescent (compression limits less than)

 

 

In a variety of capacitance types that give out, the most commonly used is X5R, X7R. All model are worth change in occurrence capacitance of the metropolis when ambient conditions changes. Especially Y5V is inside interval of whole ambient conditions, can show huge capacitance to change.

 

When capacitance company develops a product, they can pass the character that chooses material, make capacitance can be in temperature interval of the regulation (mix the first times the 2nd letter) , the job is inside affirmatory span (the 3rd letter) . What I am using is X7R capacitance, it is in – 55°C arrives + the change between 125°C does not exceed ±15% .

 

In capacitance when us two end are added when electrify is pressed, the change that we discover to voltage can bring about capacitance to be worth (in compression limits less than) . It is such that capacitance is measured as the change that sets a requirement big. What I choose is the compression 16V electric capacity that a job leaves in 12V bias voltage. Data table shows, 4.7-μF capacitance provides the capacity of 1.5μF only normally below these conditions.

 

 

We can see, different type, different compression, different enclosed capacitance, as the downtrend that voltage rises.

 

To a certain given enclose dimension and ceramics capacitance type, the rated voltage of capacitance does not have an influence commonly it seems that.

 

2, communication bias voltage is characteristic

 

Besides above the look value that descriptive volts d.c. can affect capacitance, in the communication above capacitance the quantity also can affect the look of capacitance to be worth.

 

 

3, the change as temperature, look value has the capacitance of different type to go differently situation.

 

 

4, ESR and ESL

 

Capacitor (divide in graph 3) outside having C of size class status, the resistance that because dielectric or electrode loss arise,still has (ESR) the parasitism inductance that reachs electrode or lead generation (ESL) . Accordingly, | Z | frequency character is shown 4 times like the graph submit V word model (partial capacitor may turn into U word) curve, ESR also shows as corresponding as loss value frequency character.

 

Actual capacitor

 

Of actual capacitor | Z | / ESR frequency is characteristic (exemple)

 

| Z | Turn into with ESR on the reason of graph curve is as follows:

 

Low frequency leads limits: Of low frequency limits | Z | As identical as ideal capacitor, show inverse ratio trend to decrease with frequency. ESR value also shows the character with the corresponding dielectric loss that with dielectric cent pole defer produces.

 

Near resonance dot: Frequency is elevatory, criterion | Z | Wait for those who suffer parasitism inductance or electrode the ESR influence of generation than resistor, deviate ideal capacitor (red dotted line) , indicate the least value. | Z | The frequency when be the least value is called lead from Zhen Pin, right now | Z | =ESR. If be more than,lead from Zhen Pin, criterion component character is inductance by capacitor change, | Z | Turn and increase. Call a look sexual field under the limits that leads from Zhen Pin, call perceptual field conversely.

 

ESR is affected besides what suffer interpose report loss, still suffer electrode oneself to resist the loss of the journey is affected.

 

High frequency limits: In the tall frequency limits of resonance dot above | Z | characteristic by parasitism inductance (L) decision. Of high frequency limits | Z | But by formula (2) reachs approximately, increase into direct ratio trend with frequency.

ESR shows effect of electrode hasten skin and the effect that are close to effect gradually.

 

 

Above is the frequency character of actual capacitor. Important is, frequency is taller, jump over the effect that cannot ignore parasitism composition ESR or ESL. Be in as capacitor the application of high frequency domain is increasing, ESR and ESL and static capacitance value of a quantity are same, become the important parameter that shows capacitor performance.

 

Above became minute of ESR, ESL to undertake demonstrative to the tremendous influence of frequency character with respect to capacitor parasitism. Capacitor sort is different, send raw ingredient to also can differ somewhat. Next the distinction of character of frequency of phyletic to differring capacitor undertakes demonstrative.

 

Next chart show electrostatic capacity 10uF of all sorts of capacitor | Z | The frequency that reachs ESR is characteristic. Divide film capacitor beyond, it is SMD capacitor completely.

 

Of all sorts of capacitor | Z | / ESR frequency is characteristic

 

Plan institute shows the static capacitance value of a quantity of capacitor to all be 10uF on, because this frequency is not worth the capacity limits of 1kHz | Z | All be coequal value. But when 1kHz above, aluminium electroanalysises capacitor or Tantalum electroanalysis of capacitor | Z | Than multilayer capacitor of pottery and porcelain or film capacitor are big, because aluminium electroanalysises,this is capacitor or Tantalum electroanalysis of the electrolyte material of capacitor more elevatory than resistor, bring about ESR to increase. Film capacitor or multilayer metallic data was used in the electrode of capacitor of pottery and porcelain, ESR is very accordingly low.

 

Multilayer capacitor of pottery and porcelain and make foot film capacitor the character around resonance dot is basic and identical, but multilayer of capacitor of pottery and porcelain lead from Zhen Pin tall, of inductive limits | Z | Inferior. Because brought the inductance that crural line part makes only in foot film capacitor to increase,this is.

 

By above the result can be reached, SMD multilayer capacitor of pottery and porcelain is fought in wider frequency limits internal resistance very low, the most comfortable also at high frequency utility.

 

Next graphs shorten for length L, the LW that width W increases goes against transition capacitor. By the graph medium frequency character is knowable, although the size is same, the impedance of LW changeover capacitor under general capacitor, characteristic and admirable. Use LW goes against transition capacitor, although the amount is little at general capacitor, also can acquire coequal property, through reducing component the amount can reduce cost, cut fact packs an area.

 

LW goes against the exterior of transition capacitor

 

 

5, invalidation

 

Multilayer a capacitor of shape contented interpose by medium of pottery and porcelain, upright electrode, metal electrode 3 kinds of material are formed, invalidation form is fault of the layer between metal electrode and Tao Jiezhi, electric expression is get outside force (if bend gently bat or touch with soldering-iron head) pound with temperature (if iron solders) when capacitance stand or fall.

 

Multilayer a capacitor of shape contented interpose is specific and undesirable can divide for:

 

1, heat attacks be no longer in force

2, screwy burst invalidation

3, raw material invalidation 3 kinds big

 

(１ ) heat attacks failure mode:

 

Heating up the principle that attacks be no longer in force is: Making multilayer when capacitance of pottery and porcelain, the different hot coefficient of expansion that uses all sorts of compatible material to be able to cause internal occurrence tension and heat conduction are led. Transform when temperature when rate is too old because heat is attacked,appear easily and cracked phenomenon, this kind of burst often from the structure the weakest reach rigid structure most happen when concentration, it is to be close to commonly appear the interfacial place of termination and termination of central pottery and porcelain, place that produces the largest mechanical pulling force (be in commonly crystal is the hardest quadrilateral) , and heat attacks create a variety of appearances possibly:

 

The first kind of form that is clearly is like fingernail or U- form crack Jun

 

 

The 2nd kind is the tiny break that conceals inside

 

 

The 2nd kind of break also is met by bare and outer central part, or pottery and porcelain / the bottom of termination interface begins, follow the change of temperature, or undertake at assembling when, spread down twist to come (see a picture 4) .

 

 

The first kind of form is like fingernail or U- form crack Jun and the 2nd kind of tiny break that conceal inside, both distinction is latter place only the pulling force that get is lesser, and make the break that extend slighter also. The first kind of rupture that cause is apparent, can measure in metallographic commonly piece, the 2nd kind of metallographic after developing certain level only just can be measured.

 

(2) screwy burst invalidation

 

This kind of undesirable possibility is very much: It is OK to reach expression by kinds big cent is two kinds:

 

The burst invalidation that phase of the first kind of circumstance, SMT brings about

 

Put when the extraction that has a part especially SMT phase spare parts is taken when putting, because wear away,take the put claw in deciding, counterpoint is not accurate, tilt etc cause. Center the pressure that rise by the claw in deciding, can cause very great pressure or cut off rate, then forms split feature.

 

These burst phenomena are visible exterior break commonly, or 2 to the in-house burst between 3 electrode; Exterior burst can reach the way of displacement of pottery and porcelain along the strongest pressure line commonly.

 

 

Vacuum check picks up a damage that cause or burst. General meeting forms a circle or half-moon impress area in the surface of chip, and contains not pliable brim. In addition, the break of this half moon or circle sucks head photograph be identical via also be being mixed continuously.

 

Another caustic link that creates by place suction a head, the rupture that causes because of pulling force, interstitial meeting by package center at the same time extend arrives across, these break may spread to the other one side of package, and its coarse crack may make the bottom damaged of capacitor.

 

 

The 2nd kind, the burst invalidation that stage of production brings about after SMT

 

When installation ﹑ reachs rear component of ﹑ of test of ﹑ of circuit board cut and connector to be assembled finally, if soldering tin component gets screwy or after soldering tin process circuit board is pulled straight, cause ’ of ‘ screwy burst likely this kind attaint.

 

Below mechanical power effect plank bends when be out of shape, the territory of pottery and porcelain accepts end position and solder dot restriction, burst can be in the termination interface place of pottery and porcelain to form, this kind of burst can begin from formation place, spread to termination from 45° horn.

 

 

(3) raw material invalidation

 

Multilayer capacitor of pottery and porcelain has 2 kinds big normally kind of fundamental visible and in-house flaw that enough damages product reliability:

 

The invalidation between electrode reachs burst of combustion of combinative line burst.

 

These blemish can cause voltaic excess, damage the dependability of package consequently, define as follows:

 

1, the invalidation between electrode and combinative line burst are main by the high gap of pottery and porcelain, or dielectric layer and the space that exist between electrode relatively are caused, make dielectric layer fission is between electrode, become crisis of latent leakage of electricity;

 

2, combustion cracked character and electrode are perpendicular, and come from electrode brim or terminal commonly. If show burst,be perpendicular word, criterion they should be by combustion place is caused;

 

 

Remarks: Raw material invalidation kind in because the first kind of invalidation is parallel detached degree measures structure of capacitance interior layer not easily piece, metallographic of the 3rd kind of perpendicular structure can assure to measure piece

 

Attack the rupture that causes to be able to spread to package interior by the surface by heat, and the harm that place of too great mechanical sex tension causes, can form by package surface or interior, these damaged all can spread with the direction close to 45° horn, as to raw material invalidation, can bring as perpendicular as in-house electrode or parallel burst.

 

Additional: Heat attacks burst to spread to another termination by a termination commonly, by take put machine the rupture that cause, appear below termination many split feature, and because circuit board is screwy and the damage that cause, has place of a burst only normally.