1) Name: Polyester (Polyester) Capacitance (CL) Symbol: Capacity: 40P - 4U Rated Voltage: 63--630V Main Features: Small volume, Large Capacity, Heat Resistance, Stability Poor Application: Stability and Low frequency circuitry with low loss requirements: Polystyrene capacitance (CB) Symbol: capacitance: 10p - 1u Rated voltage: 100V - 30kV Main features: stable, low loss, large application: stability And a high loss requirement: Polypropylene capacitor (CBB) Symbol: capacitance: 1000p - 10u Rated voltage: 63--2000V Main features: performance and polybenzene, small size, slightly different stability : Instead of most of the polybenzene or mica capacitors, used for high circuit 4) Name: Mica capacitor (CY) symbol: capacitance: 10P - 0.1U Rated voltage: 100V - 7kV Main Features: High Stability , High reliability, temperature coefficient: high frequency oscillation, pulse and other requirements high circuit 5) Name: High frequency porcelain capacitor (CC) symbol: capacitance: 1--6800P Rated voltage: 63--500V main Features: high frequency loss, good stability application: high frequency circuit 6) Name: low frequency porcelain card capacitor (CT) symbol: capacitance: 10P - 4.7U Rated voltage: 50V - 100V Main features: small size, Qi, loss, stability, high frequency circuit 7) Name: Glass glaze capacitor (CI) symbol: capacitance: 10P - 0.1U Rated voltage: 63--400V Main features: Stability Good, small loss, high temperature resistance (200 degrees) application: pulse, coupling, bypass, etc., 8) Name: Aluminum electrolytic capacitor symbol: capacitance: 0.47--10000U Rated voltage: 6.3--450V main features : Small size, large capacity, large loss, leakage applications: power filter, low frequency coupling, decoupling, bypass 9) Name: Tantalum electrolytic capacitance (CA) electrolytic capacitance (CN) Symbol: capacitance: 0.1 --1000U Rated Voltage: 6.
Main features: loss, leakage, less aluminum electrolytic capacitance application: instead of aluminum electrolytic capacitance in required circuits) Name: Air medium variable capacitor symbol: variable capacitance: 100--1500P main features: loss Small, high efficiency; can be made to the requirements of linear, linear wavelength, linear frequency and alignment, electronic instruments, radio television equipment, etc. 11) Name: Thin film medium variable capacitor symbol: variable capacity: 15 --550P main characteristics: small size, light weight; large application of loss than air media: communication, broadcast receiver, etc. 12) Name: Thin film medium fine-tuning capacitor symbol: variable capacitance: 1--29P main features: loss Large, size, small application: Circuit compensation for computers, electronic instruments 13) Name: ceramic medium fine adjustable capacitor symbol: variable capacitance: 0.3--22P Main features: less loss, small application: precision tuning High-frequency oscillation circuit 14) Name: The monolithic capacitor capacity is large, the size is small, the reliability is high, the capacitance is stable, and the high temperature resistance is good. Application range: Widely used in electronic precision instruments. Various small electronic devices have resonant, coupled, filtered, and bypass. Capacity range: 0.5PF - 1UF withstand voltage: twice rated voltage. The monolith is also called multi-layer ceramic capacitors, divided into two types, typically 1 performance, but the capacity is small, typically less than 0.2u, and the other is called II, the capacity is large, but the performance is general. The maximum shortcomings of monolithic capacitors is that the temperature coefficient is very high, and the stable drift of the oscillator can't stand. We do a 555 oscillator, the capacitor is just next to 7805, after booting, use the oscilloscope to watch the frequency, look slowly Change, then replaced with polyester capacitance. Water drift: monolith is about 130 or so, CBB is a negative temperature coefficient -230, in parallel with appropriate proportion, can make warm drift to a small. In terms of price:, niobium capacitors are the most expensive, the monolithic, the CBB is cheap, the porcelain is the lowest, but there is a high-frequency zero-cherished porcelain slight slightly more expensive. Mica capacitor Q is higher, too expensive. ---------------------------------------- Electrolytic capacitors design, a little experience: 1. Electrolytic capacitance is from 1.2 to 1.5 times that takes a voltage value of the noise peak according to the specific case in the filter circuit, and does not depend on the rated value of the filter circuit; 2. The electrolytic capacitor should not have a pad and via. 3. The electrolytic capacitor must not be in direct contact with the surrounding heat generating elements. Circuit Design (4) Aluminum electrolytic power is negative electrode, does not increase the opposite voltage and AC voltage, and use a non-polar capacitance to the possibility of reverse voltages. (5) For places that need to be quickly charged and discharge, the aluminum electrolytic capacitor should not be used, and specially designed capacitors have a longer life. (6) Should not use overload voltages 1. The sewing voltage after the DC voltage jadeboli is lower than the rated value. 2. Two or more electrolytic capacitors are used in series to consider using a balance resistor such that the voltages on each capacitor are within its rated range. (9) When designing a circuit board, pay attention to the upper end of the capacitance to prevent the explosion valve must not have any lines, and should leave a gap of 2mm or more. (10) Electrolysis also main chemical solvents and electrolytic paper as flammable materials, and electrolyte conductivity. When the electrolyte is in contact with the PC board, the line on the PC plate may be corroded. To smoke or catch fire. Therefore, there should be no lines under the electrolytic capacitance.
(11) Designing circuit board to check to confirm that the heat generating device is not close to aluminum electrolytic capacitance or electrolytic capacitance ---------------- ------------ Capacitor model naming: 1) The model naming of various capacitors is not uniform, and the naming of domestic capacitors consists of four parts: Part 1: Name with letters, capacitors C. The second part: The material is represented by letters. Part III: Classified by numbers. Part IV: Sequence numbers are indicated by numbers. 2) Logo method for capacitance: (1) direct standard method: Use letters and numbers to mark the model, specification directly on the housing. (2) Text symbolic method: The capacity is represented by a combination of numbers, text symbols. The text symbol represents the unit of its capacitance: P, N, U, M, F, etc. And the representation of the resistance is the same. The nominal allowance deviation is also the same as the representation of the resistance. Less than 10PF capacitors allows the deviation to be replaced by: B - ± 0.1PF, C - ± 0.2PF, D - ± 0.5PF, F - ± 1PF. (3) Color scale: The same as the resistance is said, and the unit is generally PF. The pressure resistance of the small electrolytic capacitor also uses the color label, the position is close to the root of the line, the meaning shown in the following table: color black brown red orange yellow green blue violet with pressure 4V 6.3V 10V 16V 25V 32V 40V 50V 63V 15) Safety capacitance refers to the use of such an occasion, that is, after the capacitor is invalid, it will not lead to electric shock, not endangering personal safety. The peak pulse voltage over voltage allowed in safety capacitance security level (IEC664) X1> 2.5 KV ≤4.0kV III X2 ≤ 2.5kV II X3 ≤1.2kV - 16) Safety Capacitance Safety rating Insulation Type Rated Voltage Range Y1 Double Insulation or Strengthen Insulation ≥ 250V Y2 Basic Insulation Or Additional Insulation ≥ 150V ≤250V Y3 Basic insulation or Additional insulation ≥ 150V ≤250V Y4 Basic insulation or additional insulation <150V Y capacitors must be limited, thereby achieving control of the size of the leakage current flowing through its leakage current under the rated frequency and rated voltage, affecting the performance of the system EMC purpose. GJB151 specifies that the capacity of Y capacitors should not be more than 0.1uf. The Y capacitors are required to comply with the corresponding grid voltage withstand voltage, and this capacitor is required to have sufficient safety balance in electrical and mechanical properties to avoid breakdown short circuits in extreme harsh environment, and the pressure resistance of Y capacitors. Protecting personal safety parameters for confidence capacitors Select X capacitors, polystyrene (thin film ethylene) capacitance, can also be seen from the above posts, polystyrene is high, suitable for high pressure pulses of EMI circuitry Absorption. 2. Capacity calculation: General two-stage X capacitors, the previous stage with 0.47uF, the second basis 0.1uf; single stage is 0.47UF. There is currently no convenient calculation method. (Capacitor capacity and powerless powerless powerless relationship) Capacitance model Name: 1) Model naming of various capacitors is not uniform, domestic capacitors are named by four parts: Part 1: Name with letters, capacitors C.
The second part: The material is represented by letters. Part III: Classified by numbers. Part IV: Sequence numbers are indicated by numbers. 2) Logo method for capacitance: (1) direct standard method: Use letters and numbers to mark the model, specification directly on the housing. (2) Text symbolic method: The capacity is represented by a combination of numbers, text symbols. The text symbol represents the unit of its capacitance: P, N, U, M, F, etc. And the representation of the resistance is the same. The nominal allowance deviation is also the same as the representation of the resistance. Less than 10PF capacitors allows the deviation to be replaced by: B - ± 0.1PF, C - ± 0.2PF, D - ± 0.5PF, F - ± 1PF. (3) Color scale: The same as the resistance is said, and the unit is generally PF. The pressure resistance of the small electrolytic capacitor also uses the color label, the position is close to the root of the line, the meaning shown in the following table: color black brown red orange yellow green blue violet with pressure 4V 6.3V 10V 16V 25V 32V 40V 50V 63V (4) Flag of imported capacitors: Import capacitors typically have 6 components. The first item: The category is expressed by the letter: the second item: uses two numbers to indicate its shape, structure, packaging method, lead start and the relationship with the axis. Third item: Temperature characteristics of temperature compensation capacitors, useful letters, also useful color, its significance is shown in the following table: Sequence letter color temperature coefficient allows deviation letter color temperature coefficient Allow deviation 1 A gold 100 r Yellow-220 2 B gray 30 s green-330 3 C black 0 T blue-470 4 g ± 30 U purple -750 5 h brown -30 ± 60 V -1000 6 J ± 120 W -1500 7 k ± 250 x -2200 8 L red-80 ± 500 y -3300 9 m ± 1000 z -4700 10 N ± 2500 SL 350 ~ -1000 11 P Orange -150 YN-800 ~ -5800 Remarks: unit 10E -6 / ° C in temperature coefficient; allow The deviation is%. The fourth item: Numeria and letters indicate the pressure, the alphabet represents the effective value, and the number represents the power of 10 multiplier. The fifth item: Nominal capacity, expressed with three digits, the first two are valid values, the third is the power of 10. When there is a deciation, use r or p. The unit of ordinary capacitor is PF, and the unit of electrolytic capacitor is UF. Sixth item: Allow deviations. Use a letter, meaning and the same domestic capacitor. There is also the same as the color label, the meaning of the standard, and the logo method of the domestic capacitor. 3. Main characteristic parameters of capacitance: (1) Capacity and error: the actual capacity and the maximum range of bias allowed by nominal capacitance. Generally, it is classified: ± 5%, II ± 10%, III ± 20%. In some cases, there is also a level 0, the error is ± 20%. The allowable error of the precision capacitor is small, while the error of the electrolytic capacitor is large, and they use different error levels. Common capacitors The precision level and the representation of the resistor are the same. Expressed with the letter: D - 005 - ± 0.5%; F - 01 - ± 1%; G - 02 - ± 2%; J - I - ± 5%; K- -II - ± 10%; M - III - ± 20%. (2) Rated working voltage: The capacitor can be very stable, reliably, and the maximum DC voltage, which is also known as the maximum DC voltage.
