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What’s the capacitor unit and its labeling methods?

What's the capacitor unit and its labeling methods

Capacitor is a kind of component that can store electrical energy, it is one of the very common electronic components, almost all electronic products, capacitors are used, there are many kinds of capacitors, for the plug-in capacitors, it is generally marked with many important parameters, such as brand, capacity, capacity error, rated voltage, etc., many people can not read the capacitor parameters. This article will be a comprehensive introduction to the capacitor unit and its labeling methods.

 The function and representation of capacitor

Capacitor consists of two metal poles with an insulating medium sandwiched between them. Capacitance is mainly used for inter-stage coupling, filtering, decoupling, bypassing and signal tuning because of its characteristics of direct current flow. Capacitance is expressed by “C” plus a number in the circuit, for example, C8, which means the capacitor numbered 8 in the circuit.The function and representation of capacitor

Capacitor unit and withstand voltage

The basic unit of capacitance is F (law), other units are: millifares (mF), microfares (uF), nanofares (nF), picofares (pF). Because the capacity of the unit F is too large, so we see the units are generally μF, nF, pF. Conversion relationship: 1F = 1000000μF, 1μF = 1000nF = 1000000pF.

Each capacitor has its voltage withstand value, which is expressed in V. Generally, the nominal voltage withstand value of induction capacitors is relatively high: 63V, 100V, 160V, 250V, 400V, 600V, 1000V, etc. The voltage withstand of polarized capacitors is relatively low, generally the nominal voltage withstand values are: 4V, 6.3V, 10V, 16V, 25V, 35V, 50V, 63V, 80V, 100V, 220V, 400V, etc.

Capacitor capacity tolerance

Capacitance capacity error is indicated by the symbols F, G, J, K, L and M. The allowable errors correspond to ±1%, ±2%, ±5%, ±10%, ±15% and ±20%, respectively.

Capacitor labeling methods

1. Direct marking method

The direct marking method is to mark the nominal capacity and allowable deviation directly on the capacitor, referred to as the direct method. There are two kinds of direct indication method: direct indication method of marking unit and direct indication method of not marking unit.

Some of the direct labeling method often omit the integer unit “0”, such as 0.01μF said 0.01μF; some use R to indicate the decimal point, such as R47μF said 0.47μF.

2. Digital labeling method-1

The digital labeling method is a direct labeling method that only marks the number but not the unit, which is limited to two kinds of capacitors with the unit of pF and μF. For example, polyester capacitor or porcelain capacitor is marked with “3”, “47”, “680” and “0.01”, which means 3pF, 47pF, 680pF and 0.01μF respectively.

3. Digital letter labeling method

Digital letter labeling method is the nominal capacity of the integer part written in the unit before the decimal part written in the unit after the labeling method. For example, 1.2pF3300pF are labeled 1p2,3n3.

4. Digital labeling method-2

The digital labeling method uses three digits to indicate the nominal capacity, where the first and second digits are valid numbers and the third digit is the Nth power of 10. : <1g=1000uf> <1m=1uf=1000pf>

For example, for a capacitor labeled 472, the first two bits can be read directly, and the third bit is the second power of 10 that should be 47 10²=4700pF, which is equal to 4.7nF.

5. Marking method

Usually not a decimal point, but a unit integer, separating the decimal part. For example: 6G8=6.8G=6800UF; 2P2=2.2PF; M33=0.33UF; 68n=0.068UF Some capacitors are digitized, the first 2 digits are the two effective numbers of capacitors, and the third digit is the number of “zeros” after the effective number. The digital suffix J (5%), K (10%), M (20%) represents the error level. Such as 222K=2200PF+10%, special attention should be paid not to mix J, K, M with resistor mark, and not to mistake the capacitor as resistor.

15MFD’s is MFD is the Japanese marking method. 1MFD=1UF, here U is actually μ, so both of these two capacitors are 15μf, withstand voltage AC voltage 10000 volts.

6. Color Code labeling method

The color-coded representation is similar to the digital representation. The difference is that instead of a number, it uses a color to represent a certain number. The colors black, brown, red, orange, yellow, green, blue, purple, gray and white represent 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9, respectively. The unit is also pF.If the first color ring is brown, the second color ring is black, and the third color ring is yellow, the digital number is 104, i.e., 0.1 μF.

Labeling method of high voltage capacitors

Labeling method of high voltage capacitors

There are many manufacturers that use the number labeling method for capacity labeling. In this method, three digits are generally used to indicate the capacity size, the first two digits indicate the effective number, and the third digit is the power of 10. For example, 102 means 10x10x10PF=1000PF, 203 means 20x10x10x10PF, and in the production process of some special material high-voltage capacitors, the color-coded method is often used.

This method is along the direction of the capacitor lead, with different colors to indicate different numbers, the two rings in front indicate the electric capacity, and the third color indicates the number of zeros after the effective number (unit is pF). The color represents the value of: black = 0, brown = 1, red = 2, orange = 3, yellow = 4, green = 5, blue = 6, purple = 7, gray = 8, white = 9.

How many uf is the capacitor 152?

This method of expressing electric capacity is also called the three-digit expression, also known as the digital expression of electric capacity. The first two digits of the three-digit number is the effective number of nominal capacity, the third digit of the number of zeros after the effective number, their units are pF. For example: 102 means the nominal capacity of 1000pF, 221 means the nominal capacity of 220pF. 224 means the nominal capacity of 220,000pF.How many uf is the capacitor 152
According to the above explanation, 152 = 1500 PF, and how much uf is that? The specific conversion formula is as follows.


When 3 digits are used to identify capacitors, most cases conform to the following rule, e.g.

● 104 means the capacitance is 100000PF (that is, 10 followed by 4 zeros) = 100NF = 0.1uf

● 223 means the capacitance is 22000PF (that is, there are 3 zeros after 22) = 22NF = 0.022uf.


Reading capacitors is an important part of understanding capacitors, mainly based on some marking information on the capacitor itself to understand the parameters related to the capacitance pole of that capacitor. We hope the above will help you to understand capacitance units and labeling. More information can be obtained by visiting our website-IBE.



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