Voltage Divider Calculator
A voltage divider uses two series resistors to produce an output voltage that is a fraction of the input voltage. The output voltage is Vout = Vin x R2 / (R1 + R2). This calculator also computes the current through the divider and power dissipated by each resistor.
The voltage divider is one of the most fundamental circuits in electronics. It consists of two resistors in series connected across a voltage source. The output is taken across the bottom resistor (R2). The formula Vout = Vin × R2 / (R1 + R2) assumes negligible load current.
Voltage dividers are used to scale down voltages for measurement by ADCs, create reference voltages, and bias transistors and op-amps. For example, to read a 12V battery with a 3.3V microcontroller ADC, you would use a divider that scales the voltage by 3.3/12.
An important limitation is that voltage dividers are load-sensitive. If a load draws significant current from the output, it effectively parallels R2, reducing the output voltage. For this reason, voltage dividers work best when the load impedance is at least 10 times greater than R2. For heavy loads, use a voltage regulator instead.