electrical Calculator Scenario

Resistor Calculation for 5mm LED on 12V

Running indicator LEDs from 12V automotive or power supply systems requires current-limiting resistors.

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Key Considerations

  • 1Standard 5mm LEDs: 20mA typical, 2.0-3.5V forward voltage
  • 2Red/Yellow LEDs: ~2.0V, Blue/White LEDs: ~3.0-3.5V
  • 3Use 1/4W resistors for single LEDs
  • 4Consider LED drivers for multiple LEDs

Scenario Parameters

supply Voltage
12
led Forward Voltage
2
led Current
20
leds In Series
1
parallel Strings
1

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