Voltage divider calculator
Output voltage from two resistors, plus the current the divider wastes and why the load changes the answer.
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Output voltage
3.33 V
Vin × R2 ÷ (R1 + R2)
Current through the divider
1.67 mA
Flowing all the time, whether anything is connected or not.
Wasted as heat
8.33 mW
Whatever you connect to the output changes it. The load sits in parallel with R2, so keep the divider's own current at least ten times what the load draws. A divider cannot power a motor, a relay or a servo — for a lower supply rather than a lower signal, use a regulator.
Where this comes from
The number is the easy part. If you have to explain it to a panel, read the write-up — it goes through the formula, the assumptions and the mistakes that make the answer wrong.
Ohm's law and powerV = I R and P = V I, with the series and parallel rules, the voltage divider, and how to pick a resistor that will not cook.Other calculators
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