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    LED resistor calculation

    As a rule, the resistor for an LED is calculated using Ohm's law. To use the formula and determine the resistance value, you need to have minimal data - current and voltage.

    To calculate the resistor for an LED, you can use a convenient calculator. By entering the necessary data and selecting the type of connection to be used, all calculations will be performed automatically.



    Type of connection


    Power supply voltage  Volt
    LED forward voltage  Volt
    Current through the LED  Milliampere
    Number of LEDs  pcs.
    Exact resistor value  Ohm
    Standard resistor value  Ohm
    Minimum resistor power  Watt
    Total power consumption  Watt

    When calculating, we use the formula R = V / I
    Where:
    V – is the voltage across the resistor (V=S-VL);
    I - current passing through the resistor;
    From which it follows: R = (VS - VL) / I

    Sequence of connection
    To connect several LEDs, you need to perform this procedure sequentially. This will contribute to the least consumption of electrical energy and allow the connection of a large number of diodes simultaneously. This method is used on garlands.
    The main conditions when connecting: diodes must be of the same type, and the power supply must have sufficient power.

    How to perform the calculation:
    For example, when the power supply voltage is VS 9V, and the diode current is 0.015A
    We have the following calculations: R = (VS - VL)/I = (9 - 6)/0,015 = 200Ohm
    A 220 Ohm resistor is required. You should use the nearest higher value.