Example 50 Hz, 230 V to 12 V
Worked inputs. Not an EI lamination row.
Worked example
Turns per volt 4.6922 /V
TPV = 1 / (4.44 * f * Bmax * Ac * 10^-4)
Primary
Primary turns 1079.2042
Np = Vp * TPV
Primary wire area 0.1667 mm2
Area mm2 = current / J
Primary ohms 2665.6589 ohm
Zp / Zs = (Np / Ns)^2
Secondary
Secondary turns 59.1216
Ns = Vs * TPV * (1 + regulation)
Secondary wire area 2.6667 mm2
Area mm2 = current / J
Fill factor 28.1271
Kw = (Np * Ap + Ns * As) / window
Kw is above 0.38.
Estimated Ac 1.6263 cm2
Ac = C * sqrt(VA / f)
This is not approval to build a mains power supply. Insulation, temperature rise, and safety are not checked.
1.15 is the CRGO silicon-steel constant only if you enter it. The 2.5 to 3.5 A/mm2 range is a note, not a stored row.