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Calculates resistor value needed to limit current through an LED to safe operating levels. Prevents LED burnout and extends lifespan.

सूत्र

Formula: R = (V - Vf) ÷ I
R
(V - Vf) ÷ I — (V - Vf) ÷ I
V
V value — Variable used in the calculation
Vf
Vf value — Variable used in the calculation
I
I value — Variable used in the calculation

चरण-दर-चरण मार्गदर्शिका

  1. 1Supply voltage (V)
  2. 2LED forward voltage (typically 1.5-3.5V)
  3. 3Desired LED current (typically 2-20mA)
  4. 4Formula: R = (V - Vf) ÷ I
  5. 5Select nearest standard resistor value

हल किए गए उदाहरण

इनपुट
LED 2V, supply 5V, 20mA
परिणाम
150ohm resistor

सामान्य गलतियां जिनसे बचना है

  • Using incorrect LED forward voltage for color
  • Not accounting for voltage supply variation

अक्सर पूछे जाने वाले प्रश्न

What happens without current limiting resistor?

LED draws maximum current, burns out immediately, and can damage power supply.

How do I select resistor wattage?

Power = V × I; select resistor rated 2× calculated power for safety margin.

सेटिंग्स