Online Tools

How Does the LED Current Limiting Resistor Calculator Work?

The LED resistor calculator is a tool that helps determine the correct resistance value to be used in a circuit with LEDs. It allows you to design your LED circuit and choose the best current limiting resistor values.

The calculator requests some essential information to perform the calculations. This information includes:

• Supply voltage: The voltage of the power supply you're using to power your LEDs. This can vary depending on the type of power supply you're using.
• LED voltage: The typical voltage drop of an LED when it's on. This varies according to the LED color. For example, a red LED might have a voltage drop of 1.8V, while a blue LED might have a voltage drop of 3.6V.
• LED current: The recommended rated current for the LED. This is specified by the LED manufacturer and is usually provided in milliamperes (mA).

Based on this information, the calculator performs the following calculations: It calculates the current limiting resistor: The calculator uses Ohm's Law (V = I * R) to determine the required resistance value. It subtracts the LED voltage from the supply voltage and divides the result by the LED current to get the resistance value in ohms.

It calculates the resistor power rating: The calculator also calculates the power dissipated by the resistor using the formula P = I² x R, where P is power in watts, I is current in amperes, and R is resistance in ohms.

Additionally, the calculator provides extra information, such as the nearest standard resistance value commercially available and the color bands of the resistor based on the calculated value.

It's important to remember that the values calculated by the calculator are approximate and may vary depending on the tolerances of the electronic components. Always check the manufacturer's specifications and choose the nearest commercially available resistor.

The LED resistor calculator is a useful tool for designing and properly sizing LED circuits, ensuring that LEDs operate within their specifications and have an appropriate lifespan.