⌁BenchSupply

BenchSupply / Voltage divider

Voltage dividers

Turn one voltage into a lower reference voltage.

Calculate the unloaded output of two resistors in series, including the current they draw and the heat they dissipate.

Do not use a basic divider to power a meaningful load. For a regulated supply or an ADC with low input impedance, account for load current, source impedance and tolerance.

Formula

The bottom resistor receives a fraction of the input.

Vout = Vin × Rbottom / (Rtop + Rbottom). The ratio sets the voltage, while the absolute resistor values set wasted current and sensitivity to a load. Higher values save power but can make noise and input leakage more significant.