Voltage regulation calculator

A full-load voltage of zero is rejected as invalid_input because the formula divides by that terminal voltage.

What voltage regulation means for a power supply

Voltage regulation of a power supply, transformer, or generator is the percent by which terminal voltage changes between the open-circuit condition and the rated full-load condition. The classical identity used in electrical-engineering courses and datasheets is regulation percent equals no-load voltage minus full-load voltage, divided by full-load voltage, then multiplied by one hundred: ((V_NL − V_FL) / V_FL) × 100. Negative regulation is allowed when the full-load voltage exceeds the no-load voltage, which occurs in some compound generators and over-compensated supplies that rise under load. Search phrases such as voltage regulation calculator, percent voltage regulation, and no-load versus full-load voltage all describe this directed quotient, not a line-regulation sweep against input voltage and not a resistive voltage-divider network. V_NL, sent here as no_load_voltage, is the terminal voltage with the load disconnected. V_FL, sent here as full_load_voltage, is the terminal voltage when the supply delivers its rated current. Dividing by the full-load voltage, not the no-load voltage, is the IEEE-style definition of percent voltage regulation: a perfectly stiff source has V_NL equal to V_FL and therefore zero percent regulation, while a source that sags under current shows a positive percentage. This voltage regulation calculator takes those two voltages in any consistent unit — volts, millivolts, or kilovolts, provided both fields share the same scale — and returns regulation_percent together with voltage_drop equal to V_NL minus V_FL. Because the formula divides by V_FL, a full-load voltage of exactly zero is undefined and is rejected as invalid_input rather than producing Infinity or NaN. Identical inputs always produce identical JSON because the path is pure arithmetic with no network, no random seed, and no wall clock in the computation.

Input contract, response shape, and zero full-load errors

No-load voltage may be zero, in which case regulation is negative one hundred percent when V_FL is positive. There is no unit converter, no temperature correction, and no transformer equivalent-circuit table; this is ideal two-measurement arithmetic from the voltages you already recorded. POST a JSON body with two required finite numbers: no_load_voltage, the open-circuit terminal voltage V_NL, and full_load_voltage, the rated-load terminal voltage V_FL. Aliases are accepted so forms and scripts can speak the names they already use: Vnl, vnl, v_no_load, no_load, or V_NL for the no-load voltage; Vfl, vfl, v_full_load, full_load, or V_FL for the full-load voltage. Numeric strings parse the same way as JSON numbers. Missing fields, empty strings, non-numeric text, NaN, and Infinity all fail immediately with invalid_input naming the field, and failed validation is not charged. After both values are accepted, full_load_voltage is checked against the algebraic bound that makes the quotient defined: if it is exactly zero the task fails with invalid_input and a message that voltage regulation is undefined when full-load voltage is zero. A zero full-load voltage would divide by zero; that refusal is the entire reason a dedicated endpoint exists beside generic division widgets. On success the response echoes no_load_voltage and full_load_voltage with stable twelve-decimal rounding, reports voltage_drop as V_NL minus V_FL, reports regulation_percent as that drop divided by V_FL times one hundred, sets regulation_unit to the percent sign, sets formula to the IEEE identity, and sets method to voltage_regulation so clients can branch without sniffing shapes.

Where a voltage regulation calculator earns its keep

Use the browser voltage regulation calculator when you want an immediate check while grading a machines homework sheet, verifying a bench power-supply datasheet claim, or converting two DMM readings into a percent before you compare the figure to a specification band. Results are fully deterministic: the same two inputs always yield the same drop, the same percent, the same unit string, and the same formula label. There is no language model, no external catalog of supplies, and no randomness, so the capability is safe to pin in continuous-integration checks and reproducible lesson materials. Each successful request is one billable item at $0.002; failed validation does not consume balance. Choose units consistently: both voltages must share the same scale so the ratio is dimensionless and regulation_percent is a true percentage. If your source data mixes millivolts and volts, convert those quantities first; this endpoint does not rescale prefixes and will not guess a unit. Wire the endpoint into transformer-regulation drills, generator compounding worksheets, power-supply incoming inspection, or preprocessing steps where you already prefer explicit domain errors — such as rejecting a zero full-load voltage — over opaque widgets that cannot explain why a bad input was refused. Pair this endpoint with transformer turns or voltage-drop tools when the next step needs a different electrical quantity, or keep it standalone when the only unknown is percent regulation from two measured voltages.