Sizu Home › Calculators › LED Resistor, E12 Value & Power
Enter a supply voltage, a forward drop and a target current, then press Calculate.
From the book — Chapter 1. R = (Vsupply − Vf) ÷ I, then round UP to a real E12 value — a bigger resistor means less current, and less is the safe side of a limit.
Matches Chapter 1 exactly, including the round-up rule. Everything stays in your browser — no sign-up, nothing stored.