# How to Identify Resistors (With Pictures)

Resistors are very common components in all types of electronic circuits. Its function is to resist the flow of current in the circuit, and that resistance is measured in ohms. Most are printed with a color code or an alphabetic code to indicate their value in ohms and their tolerance (how much their resistance can vary). You can easily identify the resistors if you learn the codes, using a very useful mnemonic device.

## Steps

### Method 1 of 2: Color-Coded Resistors (Axial Resistors)

#### Step 3. Read the color bands from left to right

The colors in the first 2 or 3 bands correspond to the numbers 0 to 9, representing the significant digits of the resistor's ohm value. The last band indicates the multiplier. For example, a brown, green, and green banded resistor has 15 mega ohms (15,000,000 ohms). The code is like this:

• Black: significant digit 0, multiplier 0
• Brown: significant digit 1, multiplier 10
• Red: significant digit 2, multiplier 100
• Orange: significant digit 3, multiplier 1,000 (kilo)
• Yellow: significant digit 4, multiplier 10,000 (10 kilo)
• Green: significant digit 5, multiplier 100,000 (mega)
• Blue: significant digit 6, multiplier 1,000,000 (10 mega)
• Violet: significant digit 7
• Gray: significant digit 8
• White: significant digit 9
• Gold: 1/10 multiplier
• Silver: 1/100 multiplier

#### Step 4. Read the color in the last color band, which is on the far right

Represents the tolerance of the resistor. If there is no color band, the tolerance is 20%. Most resistors are bandless, or have a silver or gold band, but you can find resistors with other colors. The tolerance color code looks like this:

#### Step 5. Brown:

1 percent tolerance

#### Step 6. Red:

2 percent tolerance

#### Step 7. Orange:

3 percent tolerance

#### Step 8. Green:

0.5 percent tolerance

#### Step 9. Blue:

0.25 percent tolerance

#### Step 10. Violet:

0.1 percent tolerance

#### Step 11. Gray:

0.05 percent tolerance

#### Step 12. Gold:

5 percent tolerance

#### Step 13. Silver:

10 percent tolerance

#### Step 14. Memorize a mnemonic system for resistors

There are many, choose one that you cannot forget. Remember that the first color is black, and after that, each letter corresponds to a color in order from 0 to 9. One of the methods to memorize is this:

### Method 2 of 2: Alphanumeric Coded Resistors (Surface Resistors)

#### Step 1. Surface resistors are rectangular in shape with terminals on opposite sides or on the same side, and are folded forward to mount on printed circuits

Some resistors have contact plates on the bottom.

#### Step 2. Read the 3 or 4 numbers from the resistor

The first 2 or 3 represent the significant digits, and the last indicates the number of zeros that follow. For example, a resistor that reads 1252 will indicate a resistance of 12,500 ohms, or 1.25 kilo-ohms.

#### Step 4. A:

0.05 percent tolerance

#### Step 5. B:

0.1 percent tolerance

#### Step 6. C:

0.25 percent tolerance

#### Step 7. D:

0.5 percent tolerance

#### Step 8. F:

1 percent tolerance

#### Step 9. G:

2 percent tolerance

#### Step 10. J:

5 percent tolerance

#### Step 11. K:

10 percent tolerance

#### Step 12. M:

20 percent tolerance

#### Step 13. Check if there is a letter R in the number code

It indicates that it is a very small resistor, and that the letter acts as a decimal point. For example, a 5R5 resistor indicates that it has a resistance of 5.5 ohms.