Calculadora de Transformadores

Ingresa vueltas primarias/secundarias o voltajes para calcular la relación de transformación, corrientes y potencia. Incluye cálculos de eficiencia, regulación y diagrama de circuito SVG.

Calculation Mode

Primary Voltage (V₁)

Turns Ratio (N₁ : N₂)

VA Rating

Efficiency (%)

Common Presets

Results

Step-Down10 : 1

Output Voltage

12.0 V

Turns Ratio: 10 : 1

Output Current

8.33 A

Input Current: 833.3 mA

Apparent Power

100 VA

Real Power (Output): 95.00 W

Primary Voltage (V₁)

120.0 V

Secondary Voltage (V₂)

12.0 V

Power Loss

5.00 W

Efficiency (%)

95.0%

Transformer Schematic

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What is a Transformer Calculator?

A transformer calculator determines the voltage, current, and turns ratio relationships in electrical transformers. Transformers work on the principle of electromagnetic induction: the ratio of primary to secondary windings (turns ratio) determines the voltage transformation. The formula V₁/V₂ = N₁/N₂ = I₂/I₁ governs all transformer calculations. This calculator handles both step-up (increasing voltage) and step-down (decreasing voltage) transformers, with VA sizing and efficiency estimation.

How to Use the Transformer Calculator

Select calculation mode: Calculate Secondary (forward) or Calculate Turns Ratio (reverse)
Enter the primary voltage and turns ratio — or primary voltage and desired secondary voltage
Optionally enter the VA rating to see primary and secondary currents
Adjust efficiency to account for copper and core losses
View results including currents, power, losses, and the transformer schematic

Frequently Asked Questions

What is the transformer turns ratio formula?

The turns ratio is N₁/N₂ = V₁/V₂, where N₁ and N₂ are the number of primary and secondary turns, and V₁ and V₂ are the primary and secondary voltages. For current, the relationship is inverted: I₁/I₂ = N₂/N₁, meaning higher voltage means lower current.

What is the difference between step-up and step-down transformers?

A step-down transformer has more primary turns than secondary (N₁ > N₂), reducing voltage. A step-up transformer has fewer primary turns (N₁ < N₂), increasing voltage. The turns ratio determines the direction: ratio > 1 = step-down, ratio < 1 = step-up.

How do I size a transformer in VA or kVA?

Transformer VA rating = V₂ × I₂ (secondary voltage × secondary current). For three-phase: VA = √3 × V × I. Choose a standard VA rating that exceeds your load requirement by 20-25% for safety margin. Common sizes: 50, 75, 100, 150, 225, 300, 500, 750, 1000 VA.

What causes transformer losses?

Transformer losses include copper losses (I²R heating in windings, varies with load) and core losses (hysteresis and eddy currents in the iron core, constant regardless of load). Typical efficiency ranges from 95-99% for power transformers, with smaller transformers generally being less efficient.

What is an isolation transformer?

An isolation transformer has a 1:1 turns ratio (same input and output voltage) but provides galvanic isolation between primary and secondary circuits. This prevents direct electrical connection, protecting against electric shock and reducing noise. Common in medical equipment and sensitive electronics.