Advanced Line Regulation Calculator

Sample	Input Voltage (V)	Output Voltage (V)	Comment
Low	210.00	11.92	Lower mains condition.
Nominal	230.00	12.00	Reference operating point.
High	250.00	12.08	Upper input tolerance.

Formula Used

Line Regulation (%) = ((V_out,max − V_out,min) / V_ref) × 100

Line Regulation (V/V) = (V_out,max − V_out,min) / (V_in,max − V_in,min)

Line Regulation (mV/V) = Line Regulation (V/V) × 1000

Here, V_ref can be the nominal output voltage or the average measured output, depending on the chosen reference method. Smaller values indicate better voltage stability against input supply variation.

How to Use This Calculator

Enter three different input voltage points that represent your test range.
Enter the corresponding measured output voltage at each point.
Provide the nominal output voltage for percentage normalization.
Choose whether calculations should use nominal or average output as the reference.
Optionally enter a known PSRR estimate for comparison.
Press the calculate button to view results above the form.
Review the table, trend graph, and point deviations.
Export the result set using the CSV or PDF buttons.

Frequently Asked Questions

1. What does line regulation measure?

It measures how much the output voltage changes when the input voltage changes while load conditions remain essentially constant.

2. Why is lower line regulation better?

Lower regulation means the supply holds output voltage more steadily, which usually improves circuit reliability, accuracy, and downstream performance.

3. Why use three voltage points instead of two?

Three points reveal trend shape better, show midrange behavior, and allow a simple linear fit with visible deviation analysis.

4. Should I use nominal or average output as reference?

Use nominal output for specification-style checks. Use average measured output when you want a result centered on actual test behavior.

5. What is mV/V in this calculator?

It expresses output change in millivolts for every one-volt change in input, which is common in regulator characterization.

6. Does load current change the result?

Yes. Line regulation should ideally be tested at a fixed load. Changing load current can introduce load regulation effects and distort interpretation.

7. Is the PSRR value exact here?

No. The PSRR shown is only a rough comparison metric unless you enter a known measured value from the device test data.

8. Can this calculator replace lab instrumentation?

No. It helps organize and interpret measurements, but accuracy still depends on proper test setup, instruments, and stable operating conditions.