Vout = 1.25 × (1 + R2/R1)
For 12V: R2 ≈ 1kΩ (with R1=120Ω) ⚠️ Low efficiency (~50–60%), large transformer & heatsink needed. 2. Switching (SMPS) – Buck Converter (Efficient & Compact) Common ICs: LM2596 (3A only, not 5A), XL4015 (5A), LM2577-12 (boost), or better: LM2678-12 (5A fixed) or TPS5450 (5A). 12v 5 amp power supply circuit