By Mark Stansberry, Updated Mar 24, 2022
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Voltage regulation is the ability of a power source or regulator to maintain a stable output voltage when the load changes. Engineers evaluate this stability with a load‑regulation calculation that uses the device’s voltage under two conditions: full load (all connected equipment powered) and no load (all equipment off).
With no devices attached, measure the output voltage of the battery or regulator. In this example, the no‑load voltage is 12 V.
Connect all intended load devices, turn them on, and measure the output voltage again. Here, the full‑load voltage is 11 V.
Subtract the no‑load voltage from the full‑load voltage: 12 V – 11 V = 1 V drop.
Divide the voltage drop by the full‑load voltage: 1 V ÷ 11 V ≈ 0.091 V/V.
Multiply the result by 100: 0.091 × 100 % ≈ 9.1 %. Thus, the regulator’s load regulation is 9.1 %.
Voltage regulators keep output voltage steady under varying loads. Manufacturers specify a load‑regulation figure for a defined full‑load current. For example, a 12‑V regulator might have a 0.1 % load‑regulation rating, guaranteeing an output no lower than 11.98 V up to 300 mA. The formula for percent load regulation is 100 × (no‑load voltage – full‑load voltage) ÷ full‑load voltage. Line regulation, in contrast, measures how input voltage variations affect the output.
Always follow approved electronic safety precautions when operating electronic equipment.
