Resistor calculator
A resistor is a fundamental electronic component that is used to limit the flow of electric current in a circuit. It does so by providing electrical resistance, which is measured in ohms (symbol: Ω). Resistors are an essential part of electronic circuits and are used for various purposes, such as voltage division, current limiting, signal conditioning, and many more.
1. How Resistors Work:
- Resistors are typically made of materials that impede the flow of electrical current. This opposition to current flow is called electrical resistance.
- When a voltage is applied across a resistor, it restricts the flow of electrons, causing a voltage drop and generating heat in the process. This property is used in various applications in electronics.
- Resistors are usually made with a specific resistance value, which is expressed in ohms (Ω).
2. Calculating Resistance from Color Bands (Color-Coded Resistor):
- Many resistors are color-coded to indicate their resistance values and tolerance. A standard system of color bands is used to represent the resistance.
- The color bands are usually found on the resistor body, and they provide information about the resistance value and tolerance. The color code typically consists of four or five bands.
- To calculate the resistance value of a resistor using the color code, follow these steps:
a. Identify the first band, which represents the first digit of the resistance value.
b. Identify the second band, which represents the second digit of the resistance value.
c. Identify the third band, which represents the multiplier (the power of 10 to multiply the two digits).
d. The fourth band (if present) represents the tolerance of the resistor.
e. The fifth band (if present) may represent the temperature coefficient (PPM/°C).
- Once you have identified the colors of these bands, you can use a color code chart to determine the corresponding numeric values and calculate the resistance:
- The first and second bands provide the digits.
- The third band provides the multiplier.
- To calculate the resistance, combine the first two digits and multiply them by the multiplier.
- For example, if the first band is red (2), the second band is green (5), and the third band is orange (10^3), the resistance is 25 * 1,000 = 25,000 ohms or 25 kΩ.
Example Color Codes:
- Band 1: Red (2)
- Band 2: Green (5)
- Band 3: Orange (10^3)
- Resistance Value: 25,000 ohms or 25 kΩ
Tolerance is usually indicated by a fourth band. For example, if the fourth band is gold, it indicates a tolerance of ±5%.