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Capacitance basics
Source：http://tenglongxiefumy.cnRelease time：2015-08-31 10:30:23Views：Keywords：
Capacitance
Engaged in electronic circuit design and development, both with years of experience veteran, also joined the Road novice. Everyone MCU, DSP, embedded systems put a lot of time and energy to study, but for the most widely used circuit design, the most widely used components - capacitors, how many people can do is very clear? And this is one of many novice doubt, in the face of many capacitor types: tantalum, aluminum electrolytic, monolithic, film, ceramics, paper-like, a variety of packages: patch, pin, box , irregular, etc., in different application areas: decoupling, filtering, high frequency, low frequency, resonance, switching power supply applications, if you can make the right choice? I suggest that you be more complementary, learn from each other on the one hand, on the other hand is a help for the novice. Next initiate some quotes from the article to other sites, (the site name has not remember, now its gratitude)
Name: Polyester (PET) capacitor (CL)
Symbol:
Electric Capacity: 40p - 4u
Rated voltage: 63--630V
Main features: small size, large capacity, heat resistant and moisture, poor stability
Application: loss of stability and less demanding low frequency circuits
Name: Polystyrene capacitor (CB)
Symbol:
Electric Capacity: 10p - 1u
Rated voltage: 100V - 30KV
Main features: a stable, low loss, larger
Application: loss of stability and demanding circuit
Name: polypropylene capacitors (CBB)
Symbol:
Electric Capacity: 1000p - 10u
Rated voltage: 63--2000V
Main features: performance and polyphenylene similar but small, slightly worse stability
Application: replace most of polystyrene or mica capacitors for higher demand circuit
Name: Mica capacitor (CY)
Symbol:
Electric Capacity: 10p - 0.1u
Rated voltage: 100V - 7kV
Main features: High stability, high reliability, low temperature coefficient
High frequency oscillation circuit requirements, pulse and so on: Application
Name: high-frequency ceramic capacitors (CC)
Symbol:
Capacity: 1--6800p
Rated voltage: 63--500V
Main features: high-frequency loss, good stability
Applications: high-frequency circuits
Name: Low frequency ceramic capacitors (CT)
Symbol:
Electric Capacity: 10p - 4.7u
Rated voltage: 50V - 100V
Main features: small size, low cost, loss, poor stability
Applications: less demanding low frequency circuits
Name: glass glaze capacitors (CI)
Symbol:
Electric Capacity: 10p - 0.1u
Rated voltage: 63--400V
Main features: good stability, low loss, high temperature (200 degrees)
Applications: pulse, coupling, bypass and other circuits
Name: electrolytic capacitors
Symbol:
Capacity: 0.47--10000u
Rated voltage: 6.3--450V
Main features: small size, large capacity, loss, leakage large
Applications: Power filter, low frequency coupling, decoupling, bypass etc.
Title: But electrolytic capacitors (CA) niobium electrolytic capacitor (CN)
Symbol:
Capacity: 0.1--1000u
Rated voltage: 6.3--125V
Main features: loss, leakage is less than electrolytic capacitors
Application: instead of aluminum electrolytic capacitors in circuits requiring high
Name: air medium variable capacitor
Symbol:
Variable capacitance: 100--1500p
Main features: low loss, high efficiency; can be made according to the requirements of linear, linear wavelength, linear and logarithmic frequency type, etc.
Applications: electronic equipment, radio and television equipment
Title: film medium variable capacitor
Symbol:
Variable capacitance: 15--550p
Main features: small size, light weight; a large loss medium than air
Applications: Communication, broadcasting receivers
Title: film dielectric trimmer capacitor
Symbol:
Variable capacitance: 1--29p
Main features: a large loss, small
Applications: tape recorders, electronic equipment and other circuits for circuit compensation
Name: ceramic dielectric trimmer capacitor
Symbol:
Variable capacitance: 0.3--22p
Main features: a smaller loss, smaller
Applications: Precision tuning of high-frequency oscillation circuit
Monolithic capacitor biggest drawback is the high temperature coefficient, so the stability of the oscillator drift is intolerable, and we do a 555 oscillator capacitor in 7805 just next boot, using the oscilloscope to see the frequency, seeing it slowly change, later replaced by polyester capacitors much better.
Monolithic capacitor characteristics:
Large capacity, small size, high reliability, electric capacity and stability, moisture resistance and good high temperature.
Applications:
Widely used in electronic precision instruments. A variety of small electronic devices for resonance, coupling, filtering, bypass.
Capacity range:
0.5PF - 1UF
Pressure: twice the rated voltage.
Which said that only stone known as multilayer ceramic capacitors, two types, type 1
Performance is very good, but the capacity is small, generally less than 0.2U, another call
Type II, large capacity, but performance in general.
Just drift in terms of:
Monolithic about positive temperature Shito number +130, CBB negative temperature coefficient of -230, used in parallel with an appropriate proportion, can drift down to very small.
In terms of price:
Tantalum, niobium capacitors expensive, monolithic, CBB cheaper, tiles minimum, but a kind of high-frequency zero point drift black tiles a little expensive. High Q value mica capacitors, but also slightly more expensive.
