EngineerHub.orgHow to use this calculator
Follow the three steps below. Start with the example values, replace them with your own data, and read the result together with the assumptions and limitations.
Inputs
Results
Background
Engineering basis, equations, assumptions, interpretation and practical limitations for this calculator.
Vₛ/Vₚ = Nₛ/Nₚ
Ideally, VₚIₚ = VₛIₛ. The efficiency input increases estimated primary input current for losses.
Turns ratio alone does not determine core size, wire gauge, flux density, temperature rise, isolation or permissible VA rating.
Frequently Asked Questions
Practical questions about assumptions, inputs, interpretation and limitations.
For approximately the same transferred apparent power, reducing secondary voltage allows a proportionally higher secondary current. In an ideal transformer, voltage ratio follows turns ratio while current ratio is inverse to turns ratio.
For an ideal transformer, Vp/Vs = Np/Ns. Current follows the inverse relationship Ip/Is = Ns/Np when losses are neglected.
AC transformer voltage ratings are normally expressed as RMS because RMS voltage relates directly to heating and power in resistive loads. The turns-ratio relationship therefore normally uses RMS primary and secondary voltages.
No. Core area, flux density, frequency, volts per turn, copper current density, winding fill, insulation, leakage reactance and thermal performance require a much more detailed transformer design.
Real windings have resistance and leakage reactance, so internal voltage drops cause load regulation. Magnetizing current and core losses also make real current and power relationships differ from the ideal model.