Electronics

Ohm's law, LED & divider resistors, resistor colour codes, and circuits.

8 tools

Battery Life CalculatorEstimate how long a battery lasts from its capacity in mAh and the load current it drives.LED Resistor CalculatorSize the current-limiting resistor for an LED from supply voltage, LED forward voltage and current.Ohm's Law CalculatorFind voltage from current and resistance with Ohm's law — plus the power it dissipates.Resistor Color Code CalculatorDecode a 4- or 5-band resistor — pick each colour and read the resistance, tolerance and range.Voltage Divider CalculatorFind the output voltage of a two-resistor divider from the input voltage and resistor values.Parallel Resistance CalculatorCombine two resistors in parallel — the total is always less than the smaller one.Series Resistance CalculatorAdd up to three resistors in series — the total is simply their sum.Wire Gauge CalculatorFind the cross-sectional area of an AWG wire and a rough chassis-wiring current limit.