Electronics & Electricity

Ohm's Law Calculator

Calculate voltage, current, resistance, and power from any two known values using Ohm's law and the power law.

LED Resistor Calculator

Work out the series resistor value and power rating an LED needs from the supply voltage, LED colour, and desired current.

Battery Life Estimator

Estimate how long a battery or pack will last from its capacity and the device current draw, with common cell presets and an adjustable usable capacity factor.

Electronics & Electricity

Capacitor Charge Time Calculator

Calculate the RC time constant, the time to reach 63% and 99% charge, and a full charge progression table for a capacitor charging through a resistor from a DC supply.

Electronics & Electricity

Wire Gauge Calculator

Work out the minimum cable cross-section needed for a given current, cable run length, and maximum acceptable voltage drop, with copper or aluminium conductors and the nearest standard section and AWG equivalent.

Electronics & Electricity

Fuse Size Calculator

Work out the nominal current drawn by a device from its power and supply voltage, then get the recommended fuse or breaker rating with a safety margin for continuous or intermittent loads, for AC mains or 12V/24V DC circuits.