Enter Values
Ideal Relationships
Vp ÷ Vs = Np ÷ Ns
Ip ÷ Is = Ns ÷ Np
Voltage follows turns ratio; current changes inversely.
Example
480 V applied to 1,000 primary turns with 250 secondary turns produces an ideal 120 V secondary. At 2 A primary, ideal secondary current is 8 A.
Ideal vs. Real Transformers
Real output voltage falls under load because of winding resistance and leakage reactance. Core loss, magnetizing current, frequency, flux density, insulation, and temperature also matter.
Do not use this ratio alone to design or rewind a transformer. Winding construction and safety insulation require qualified engineering.