Super Practical Tips: Inspection Requirements And Methods Of Electronic Components----Capacitor

Capacitance: It is a physical quantity that represents the ability of a capacitor to hold charge. The amount of electricity required to increase the potential difference between the two plates of the capacitor by 1 volt is called the capacitance of the capacitor. The symbol for capacitor is C. Capacitors are one of the electronic components widely used in electronic equipment. They are widely used in DC blocking, coupling, bypass, filtering, tuned loops, energy conversion, control circuits, etc. Use C to represent the capacitance. The capacitance units include farad (F), microfarad (uF) and picofarad (pF). 1F=10*6uF=10*12pF
1 farad (F) = 1,000,000 microfarads (μF) 1 microfarad (μF) = 1,000 nanofarads (nF) = 1,000,000 picofarads (pF)
Capacitor model naming method: The model of domestic capacitors generally consists of four parts (not applicable to pressure-sensitive, variable, and vacuum capacitors). They represent name, material, classification and serial number respectively.
How to determine the polarity of an electrolytic capacitor: Just use a multimeter to measure it. Discharge the electrolytic capacitor first, and then connect the test leads to both ends. The one with the largest swing is correct, but please note: the positive pole of the pointer meter is opposite to the capacitor. The negative pole of a digital meter is the opposite, and the capacitor must be discharged between measurements. (2) Use the length of the pins to distinguish the positive and negative poles. The long leg is positive and the short leg is negative; the black block with the mark on the capacitor is the negative pole. There are two semicircles on the PCB at the location of the capacitor. The colored semicircle corresponds to the negative electrode.
Classification of capacitors:
According to their polarity, they are divided into two categories: polar capacitors (such as electrolytic capacitors) and non-polar capacitors.
According to the structure, they are divided into three categories: fixed capacitors, variable capacitors and trimmer capacitors.
Classified by electrolyte: organic dielectric capacitors, inorganic dielectric capacitors, electrolytic capacitors and air dielectric capacitors, etc.
According to the purpose, they are: high-frequency bypass, low-frequency bypass, filtering, tuning, high-frequency coupling, low-frequency coupling, and small capacitors.
Capacitor capacity indication:
1. Direct marking method: Mark directly with numbers and unit symbols. For example, 01uF represents 0.01 microfarad. Some capacitors use "R" to represent the decimal point. For example, R56 represents 0.56 microfarad.
2. Text symbol method: Use a regular combination of numbers and text symbols to express capacity. For example, p10 represents 0.1pF, 1p0 represents 1pF, 6P8 represents 6.8pF, and 2u2 represents 2.2uF.
3. Color marking method: Use color circles or color points to represent the main parameters of the capacitor. The color coding method for capacitors is the same as for resistors.
Capacitor deviation symbols: +100%-0--H, +100%-10%--R, +50%-10%--T, +30%-10%--Q, +50%-20% --S, +80%-20%--Z.
Commonly used capacitors: aluminum electrolytic capacitors, tantalum electrolytic capacitors, film capacitors, porcelain capacitors, monolithic capacitors, paper capacitors, trimmer capacitors, ceramic capacitors, glass glaze capacitors, mica and polystyrene dielectric capacitors.