Equivalent circuit for a single phase transformer with N_P turns in the primary winding and N_S in the secondary, showing:

• Primary winding resistance R_P
• Primary leakage reactance X_P
• Secondary winding resistance R_S, referred to the primary circuit by the turns ratio squared
• Secondary leakage reactance X_S, referred to the primary circuit by the turns ratio squared
• Equivalent core loss resistance R_C and core loss current I_C
• Magnetising reactance X_M and magnetising current I_M
• No-load current I₀
• Primary and secondary EMF E_P and E_S, developed over an ideal transformer
• Primary and secondary terminal voltages and currents V_P, I_P, V_S and I_S