Voltage Regulation Calculator
Find the percentage voltage regulation of a supply.
Voltage regulation measures how much a supply's voltage sags from no load to full load.
How the Math Works
The voltage regulation percentage is calculated using the formula %VR = (V_nl - V_fl) ÷ V_fl × 100, where V_nl represents the no-load voltage and V_fl is the full-load voltage. This equation measures how much the output voltage changes from when the power supply is idle versus when it's delivering its maximum current. The difference between these two voltages is normalized by the full-load voltage and converted to a percentage, giving you a standardized way to express voltage stability regardless of the supply's absolute voltage level.
Practical Applications
To use this calculator practically, measure the no-load voltage by leaving the power supply disconnected from any load, then measure the full-load voltage by connecting it to a dummy load or the actual device it will power at maximum capacity. Enter these values into the calculator to determine voltage regulation. Engineers use this measurement during power supply design and testing to ensure equipment operates within safe voltage tolerances, typically aiming for regulation values under 5% for most electronic devices.
Day-to-Day Use
This calculation helps you understand how reliably your electronic devices will perform. A power supply with poor voltage regulation might cause your computer to crash, your refrigerator's controller to malfunction, or your audio equipment to produce distortion when other devices turn on. By calculating voltage regulation, you can choose power supplies that maintain consistent voltage, ensuring your electronics run smoothly and last longer without unexpected failures or performance issues.
Worked example
12.6 V to 12.0 V → 5% regulation.
FAQ
What's a good value?
Lower percentages mean a stiffer, better-regulated supply.