SDM Resistance Code app for iPhone and iPad

The resistance value errors of SMD resistors include ± 1%, ± 2%, ± 5%, and ± 10%. The most commonly used values are ± 1% and ± 5%, with 5% represented by three digits and 1% represented by four digits. For example:

The conventional 3-digit number annotation method represents the resistance value

The conventional 3-digit labeling method is often used to represent the resistance value of the E-24 series. The accuracy is ± 5% (J), ± 2% (G), and some manufacturers also use it for ± 1% (F).

The silk screen on the resistance surface is 103:
The first two digits 10 represent the Significant figures, and the third digit 3 represents the magnification, that is, 10 ^ 3, so the resistance value of 103 resistor is 10 × 10 ^ 3=10000 Ω=10K, which is 5%.

Conventional 4-digit number annotation method
Composed of four numbers, the general error of resistance is ± 1%. The first three digits are Significant figures, and the fourth digit represents the power exponent of 10 in Scientific notation. For example, 1502150 is a Significant figures, and 2 represents the quadratic power of 10, as shown in the figure. The basic unit is Ω, i.e. XXXX=XXX *, so the resistance value of 1502 is 150 × 10 to the second power=150 × 100=15000 Ω=15K Ω.

The silk screen on the resistance surface is 1502:
The first three digits 150 represent the Significant figures, and the fourth digit 2 represents the magnification, that is, 10 ^ 2, so the resistance value of 1502 resistance is 150 × 10 ^ 2=15000 Ω=15K, which is 1%.