Power of a 3.3 V, 500 mA Microcontroller Rail
A 3.3 V logic rail supplying 500 mA draws 1.65 watts of power.
How to use this tool
- Enter voltage (v), current (i) and resistance (r) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your power and the full breakdown beneath it.
Calculate the power draw of a 3.3 V microcontroller or FPGA rail running at 500 mA, a common embedded system scenario.
Frequently asked questions
- What is the difference between this and a basic Ohm's Law calculator?
- This tool also shows power in both watts and milliwatts and lets you solve for V, I or R directly. The 'power wheel' name refers to the circular diagram in textbooks showing all 12 formula variants.
- Why do I enter 0 for the unknown?
- Entering 0 signals that the value is unknown. The calculator then derives it from the other two entered values.