Led Calculator

LED Calculator - Current limiting resistor calculator for LED arrays

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This LED calculator will help you design your LED array and choose the best current limiting resistors values. To get started, input the required fields below and hit the "Design Circuit" button.
Power supply voltage (V):  Help
LED voltage drop (V):  Help
LED current rating (mA):  Help
Number of LEDs:  Help
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  • You will need 1 x 150 ohm 1/8 watt resistor.
  • The 150 ohm resistor is color coded: Brown, Green, Brown, Gold.
  • Each 150 ohm resistor consumes 60 milliwatt.
  • Total power consumed by the resistors is 60 milliwatt.
  • Total power consumed by the LEDs is 40 milliwatt.
  • Total power consumed by the circuit is 100 milliwatt.
  • Total current drawn by the circuit is 20 milliampere.
  • The resistor values are calculated based on the common ±5% tolerance resistors.
  • Make sure to wire the LEDs in the correct direction as shown below.
  • Always leave some space for the resistors to breathe. They might get hot.

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