The first part: the name is represented by letters, and the capacitance is C.
Part II: Use letters to represent materials.
The third part: using numbers to express classification.
Part IV: Number the serial number.
2) Marking method of capacitor:
The units of capacitance are F, uF, mF, nF, pF and PF. The relationship between them is:1f =1000 MF =100000 uf,1f =1000 nf =100000 pf. The expressions specified by IEC are: m stands for11000, u stands for11000000, n stands for11000000, and p stands for/kloc-0.
(1) direct marking method: the model and specifications are directly marked on the shell with letters and numbers. Generally, two digits are used to indicate the significant number, and then a letter is used to indicate the size of the numerical value. For example, 1p2 means 1.2pF, 220n means 0.22uF, 3u3 means 3.3uf, and 2m2 means 2200uF.
(2) Text symbol method: The capacity is expressed by the regular combination of numbers and text symbols. Text symbols indicate the unit of its capacitance: P, N, U, M, F, etc. It is expressed in the same way as resistance. Nominal allowable deviation is also expressed in the same way as resistance. For capacitors less than 10pF, the allowable deviation is replaced by letters: b-0. 1pf, C—— 0.2pF, D—— 0.5pF, f- 1pf.
(3) Color coding method: It is the same as the expression method of resistance, and the unit is generally pF. The withstand voltage of small electrolytic capacitors is also measured by color code method, which is located near the root of the positive lead, and its meaning is shown in the following table:
Colors are black, brown, red, orange, yellow, green, blue, purple and gray.
Withstand voltage 4v6.3v10v16v25v2v40v 50v 63v.
(4) Marking method of imported capacitors: Imported capacitors generally consist of six items.
Item 1: Categories are indicated by letters:
Item 2: Use two figures to show its shape, structure, packaging method, lead start and relationship with axis.
Item 3: Temperature characteristics of temperature compensation capacitors, expressed in letters and colors, and their meanings are shown in the following table:
Allowable deviation of color temperature coefficient of serial number letters
1A gold+100R yellow -220
2B Grey +30S Green -330
3C Black 0T Blue -470
4 G 30 U purple -750
5 hours brown-30 60 volts-1000
6 J 120 W - 1500
Model 7 K 250 X -2200
8 liters of red -80 500 y-3300
9 m 1000 Z -4700
10n 2500 SL+350 ~- 1000
1 1 P orange-150 YN -800~-5800
Remarks: The unit of temperature coefficient is 10e-6/℃; The allowable deviation is%.
Item 4: Withstand voltage: There are also two common methods for marking capacitor withstand voltage. One is to print the withstand voltage value directly on the capacitor, and the other is the combination of numbers and letters. Numbers represent the power exponent of 10, letters represent numerical values, and the unit is V (volts).
The letter A B C D E F G H J K Z
Compressive value1.01.251.62.02.53.15.05.06.38.09.0.
For example:
1J stands for 6.3* 10=63V.
2F stands for 3.15 *100 = 315v.
3A stands for1.0 *1000 =1000v.
1K stands for 8.0* 10=80V.
The maximum number is 4, for example, 4Z stands for 90000 V.
Item 5: Nominal capacity:
Use three digits to represent the capacitance, and finally use a letter to represent the error. The first two digits in the three digits represent the effective value, and the third digit represents the n power of 10, where n is generally 1-8. The special case is that when n=9, it is not expressed as the 9th power of 10, but as the-1 power of 10.
For example:
"102" means10 *100 =1000 pf.
"223" means 22* 1000=22000pF=0.022uF.
"474" means 47* 10000=0.47uF.
"159" means15 * 0.1=1.5pf.
The unit of ordinary capacitance is pF, and the unit of electrolytic capacitance is uF.
Item 6: Allowable deviation. The letter after the significant digit indicates the error value. Due to the different materials used to make capacitors, the error ranges are also different, and some of them have great errors. The corresponding relationship between error values and letters is shown in the following table:
Comparison table of foreign capacitor capacity error and letter code
Letter D F G J K M N P S Z
Error% 0.512510 2030 (+100, -20) (+50, -20) (+80, -20).
There is also a color coding method, which means the same as the marking method of domestic capacitors.