Autotransformer Designer

Enter input/output voltage and load; results update live.

Quick presets:

Inputs

Enter input/output voltage and load.

Results

Ratio
Voltage ratio (out/in)
Currents
Input current A
Output current A
Common-winding current A
VA / Savings
Equivalent two-winding VA VA
Series winding VA VA
Common winding VA VA
VA saving vs isolation VA
Reduced-core design
Copper loss (series+common) W
Iron loss @Tcore W
Iron loss @20°C W
Copper mass kg
Window winding layout (reduced core)
Common winding Series winding
Efficiency %