Resistors... How much important is contained in this word for those who are fond of electronics or constantly working with it. However, for complete immersion in the world of electronics, it is necessary to at least superficially know and be able to determine the marking of chip resistors.
- 1 Common data SMD chips
- 2 Principles of labeling
3 Marking Interpretation
- 3.1 Plain transcript
- 3.2 Decryption through services
- 4 In conclusion
Common data SMD chips
The abbreviation “SMD” stands for Surface Mounted Devices, which means “surface mounted device». And this is true - resistors are installed above the surface on special mounts. These devices are mounted on printed circuit boards.
One of the significant advantages of smd-chips is their small size. On one PCB can be easily place dozens (if not hundreds) of similar products. Also due to high quality and low cost, resistors have gained extraordinary popularity in the electronics market.
Thanks to the constant progress, there are all new models of resistor chips, marking and characteristics of which are constantly changing. In total, there are 3 types of products in this market:
- Made in the Soviet period (now significantly losing popularity).
- Modern models.
- SMD Resistors.
In this article we will focus on the labeling of the latter type, since it is most interesting.
Principles of labeling
All SMD chips are labeled differently. The fact is that each product has its own size and tolerance value. Accordingly, in order to avoid confusion, the manufacturers decided to allocate 3 main groups for labeling:
- Products denoted by 3 digits.
- Models with 4 digits in the marking.
- Devices with 2 digits and one letter.
Each of these types should be considered in more detail.
The first group includes products (numbers 103, 513, etc.) with a tolerance of 2%, 5% or 10%. Under the first two digits of the mantissa, and the latter indicates the exponent 10. The latter value is necessary to calculate the resistor nominal value (measured in Ohms). Also, in some models there is a letter “R”, which denotes a decimal point.
To the second group, it was decided to include models with a size of 0805 and above, as well as having a tolerance of 1%. The principle is similar to the first group of resistors: the first 3 digits indicate the mantissa, and the fourth - the value of the degree, having a base of 10. In addition, here, as in the previous type, the last number implies the nominal value of the model (in ohms), and the letter R denotes the decimal point. It is worth mentioning that devices with a size of 0402 are not marked.
Finally, in the last group are smd chips with a size of 0603 and a tolerance level of 1%. The numbers indicate the code in table EIA-96 (see below), and the letter indicates the value of the multiplier:
- A - number 10 to the zero degree
- B - base 10 with degree 1
- C is the number 10 to the power of 2
- D = 103
- E = 104
- F = 105
- R = 10-1
- S = 10-2
To install or work with SMD resistor, you need to know and be able to decipher the numbers and letters. This process can be divided into 2 types.
As mentioned above, in the manufacture of smd resistors, unbreakable labeling rules apply. They are designed to the buyer could easily identify the mantissa and the resistance value. Therefore, all that is required is a leaf with a pen or a mathematical turn of mind.
Let's start with a simple example - determining the resistance of products with a tolerance of 2%, 5% or 10% (these are the models with 3 digits in the marking). Suppose on the resistor is the number 233. This means that you must multiply 23 by 10 to the third power. The result is that the product has a resistance of 23 kΩ (23 x 103 = 23 000 Ohms = 23 kOhm).
The situation is similar for models that have 4 digits in the description. For example, the product has the number 5401. Performing similar calculations, we obtain a resistance of 5.4 kΩ (540 x 101 = 5,400 ohms = 5.4 kOhm).
The situation is completely different with deciphering the designation of products with numbers and letters on them. As described above, this will require table EIA-96 (you can easily find it on the Internet). Substituting the numbers in the appropriate line and translate the letter into a numerical expression, you can easily calculate the resistance. For example, marking 04D means that the resistance is 10.7 KΩ (107 x 103 = 107,000 Ohm = 10.7 KΩ).
Decryption through services
Progress does not stand still. Modern technologies are constantly being introduced, new approaches are being developed, in other words, human life is becoming more and more comfortable. In the modern world, even for calculating the resistance of SMD chipsThere are good services and programs.
On the Internet, you can easily find many sites on which the opportunity to calculate the resistance. In most cases, this service is a calculator to calculate the resistance of the resistor. Here are just some of them:
Also specifically for this purpose was developed by the domestic program "Resistor". She in a couple of clicks allows you to find out all the information about the product. In addition, this software is absolutely free.
Decoding SMD resistors is a rather specific process. However, to fully work with chips, it is simply necessary. In addition, the knowledge gained will not be superfluous.
Quite a few people prefer to do the calculations in the old fashioned way - with a pen and notebook. Others use special software. But in any case, it is worth only a little practice - and it is easy to calculate the resistance of the resistors.