Free Electronics Tools

Pinouts, resistor codes and calculators for the bench. No signup, no ads, and every result is a link you can share.

• LED resistor calculatorSize the series resistor for any LED, with the nearest E24 values and power rating.
• Voltage divider calculatorOutput voltage, ratio and current for a two-resistor divider.
• ESP32 DevKit V1 pinoutInteractive 38-pin reference with ADC, touch and PWM flags, strapping warnings and per-pin anchors.
• ESP32-C3 SuperMini pinoutBoot-strapping guidance for the $2 RISC-V board, with flash troubleshooting notes.
• Resistor color codePick the bands of a 4, 5 or 6-band resistor to read its value, tolerance and range.
• IoT battery life calculatorDuty-cycle modelling for deep-sleep projects, with chip presets.
• WS2812B power calculatorPSU sizing, fuse and injection plan, realistic versus worst-case current.
• Voltage drop and wire gaugeRound-trip drop, the 3% rule check and the gauge to use.

A free tool from TinkerNews, the free weekly email of DIY electronics builds — ESP32, Arduino, Raspberry Pi and more.