Handyman Calculator

Parallel LED Resistor Calculator

Parallel LED Resistor Calculator helps you quickly and accurately calculate resistor for LED in parallel circuits. This tool is designed to determine the correct resistor value for each LED in a parallel configuration, ensuring that every LED receives the proper current.

Parallel LED resistor calculator diagram with multiple LEDs and resistors connected to a 12V power supply, demonstrating individual resistors for each LED.

What Is a Parallel LED Resistor Calculator?

A parallel LED resistor calculator is designed to simplify the process of calculating the resistor value required for each LED when multiple LEDs are connected in parallel. Unlike a series LED resistor calculation, the resistor calculator led parallel takes into account the fact that each LED draws its own current while sharing the same supply voltage.

This calculator ensures that the current through each LED remains within safe operating limits.

How to Calculate Resistors for Parallel LEDs

When wiring LEDs in parallel, each LED requires its own resistor to prevent uneven current distribution and burnout. Here’s how our calculator works:

Where:

  • =Power supply voltage (e.g., 12V, 5V).
  • =Forward voltage of the LED.
  • =LED current in milliamps (mA).

How Does It Work?

When using our LED Resistor Calculator Parallel, you simply input the following parameters:

  • Source Voltage: The voltage provided by your power supply.
  • LED Voltage: The forward voltage drop across a single LED.
  • LED Current: The desired current (in mA) for each LED.
  • LED Count: The total number of LEDs connected in parallel.

The calculator uses these inputs to determine:

  • Resistance: The resistor value required for each LED.
  • Power Dissipation: The power dissipated by the resistor.

Total Current: The sum of the currents for all LEDs in parallel.

Example: Parallel LED Resistor Calculation

Let’s say you want to connect 3 LEDs in parallel to a 12V battery:

  • Input Values:
    • Source Voltage (​): 12V
    • LED Voltage (​): 3.2V (common for white LEDs)
    • LED Current (​): 20mA
    • Number of LEDs: 3

Step 1: Calculate Voltage Drop Across Resistor

Step 2: Determine Resistor Value

Step 3: Calculate Power Dissipation

Step 4: Total Current Draw

Result:

  • Resistor per LED: 440Ω (use a standard 430Ω or 470Ω resistor).
  • Resistor Power Rating: At least 0.25W (higher than the calculated 0.176W for safety).

Total Circuit Current: 60mA.

FAQ

Can I use one resistor for multiple LEDs in parallel?

It's generally not recommended to use a single resistor for multiple LEDs connected in parallel. LEDs have slight variations in their forward voltage. If you use a single resistor, the current won't be distributed evenly, potentially leading to some LEDs being brighter than others or even causing premature failure.

Parallel LED Resistor Calculator

Calculate resistor values for parallel LED configurations. Each LED in parallel requires the same voltage but draws its own current. Make sure to use a resistor with a power rating higher than the calculated value.