Series resistor
Exact value
150 Ω
Nearest E24
150 Ω
Power
60.0 mW
LED resistor
Pick the exact series resistor and power rating for indicator strings.
Uses the classic LED resistor sizing formula by combining supply rail, LED forward voltage, forward current, and number of LEDs to output resistance, real power, and recommended E24 values.
5.00 V
Supply
3.00 V
Headroom
150 Ω
Resistor
Preset LED strings
Adjust count for series strings; use parallel branches with their own resistors.
Inputs
V
V
mA
pcs
LED stack
Total Vf 2.00 V. Keep at least 1 V headroom for regulation stability.
Power rating
Choose ≥0.12 W to keep the resistor cool. Round to standard ratings (0.25 W, 0.5 W, etc.).
Design notes
- Use individual resistors when driving LEDs in parallel—current sharing is unreliable otherwise.
- Add margin for LED forward voltage variation over temperature and manufacturing spread.
- For PWM dimming, ensure headroom remains even at maximum battery voltage.