Professional EI & EE core transformer design tool. Supports multi-secondary outputs, copper & core loss, efficiency prediction, temperature rise, BOM generation and PDF export.
Step 1 — Select transformer type
⚙️EI Core Laminated
🔋EE Core Ferrite/SMPS
🛡️Isolation Transformer
🔄Auto Transformer
⚡Inverter Transformer
🍩Toroidal
Step 2 — Electrical parameters
Apparent power
D = tongue (centre-leg) width. Sets core area Ac = D × stack.
Applied as-is to every core in the grid (overrides the D-multiple above).
Secondary outputs
Add up to 4 secondary windings (e.g. 24V + 12V + 5V).
Wire gauge standard
Step 3 — Core / bobbin selection
Fitness score based on VA, window product (Ap = Ac×Aw), copper fill, flux density and thermal margin.
Green = best fit · Cyan = good · Purple = acceptable
Step 2 — SMPS electrical parameters
Step 3 — EE ferrite core selection
Green = recommended for your power level. EE5 through EE110.
Toroidal Design Advisory
Same EMF formula as EI cores: N = V / (4.44 × f × Bm × Ac)
Core area Ac = (OD − ID) / 2 × HT (cm²) | Window = π × (ID/2)²
Fill factor Kw typically 0.20–0.25 (manual winding)
Common materials: CRGO tape-wound, amorphous, nanocrystalline
Core fitness = weighted score of: VA match (30%), window product Ap (25%), copper fill % (20%), flux density margin (15%), thermal margin (10%).
Window product Ap = Ac × Aw. Required Ap = VA / (Kw × J × Bm × 4.44 × f × √2). Industry standard sizing method.
Copper loss = Σ(I² × R) per winding. Resistance estimated from wire length (mean turn length × turns) and resistivity of copper (0.0172 Ω·mm²/m at 20°C, corrected to 75°C).
Core loss: CRGO ≈ 1.0–1.5 W/kg at 1.4 T / 50 Hz; CRNGO ≈ 2.0–3.0 W/kg. Ferrite N87 ≈ 80 kW/m³ at 0.2 T / 100 kHz (Steinmetz).
Temperature rise ΔT ≈ P_total / (k × Surface_area). k = 6 W/(m²·°C) natural, 12 W/(m²·°C) forced air. Surface area estimated from core outline dimensions.
Mean turn length (MTL) estimated as 2×(window_width + window_height) + π×core_leg_width per winding build.
T-series (Indian) to EI mapping: T-number ≈ EI dimension / 5. Both are displayed in the core selector.
SWG (British Standard Wire Gauge) is the standard in India. AWG (American) and metric mm² equivalents shown for reference.