Power & Efficiency Formulas
Power and efficiency formulas quantify how much energy a system delivers versus how much it wastes as heat. These calculators evaluate converter efficiency, loss, and dissipation so you can target thermal and battery budgets. They are key to designing supplies that run cool and last long.
Power & Efficiency Formula Calculators
- Linear Regulator Dissipation P = (Vin − Vout) × I
- Efficiency η = Pout / Pin
- Buck Converter Vout = Vin × D
- Boost Converter Vout = Vin / (1 − D)
- Peukert Effect t = C / I^k
- Energy After Losses Eout = Ein × η
- Solar Charge Time t = (Cap × V) / (P × η)
- LDO Minimum Output Vout_min = Vin − Vdrop
- Buck Converter Input Current Iin = Iout × Vout / (Vin × η)
- SMPS Output Voltage Ripple ΔV = Iout × D × (1−D) / (f × C)
- SMPS Inductor Current Ripple ΔI = Vin × D / (f × L)
- Three-Phase Power P = √3 × VLL × IL × cos(φ)
- Flyback Converter Turns Ratio Np/Ns = Vin×D / (Vout×(1−D))
- Charge Pump Output Voltage Vout = N × Vin − N × Vf
- Buck-Boost Duty Cycle D = Vout / (Vin + Vout)
- Forward Converter Output Vout = Vin × D × N2/N1
- SMPS Input Filter Inductor L = Vin / (ΔI × f)
- Half-Bridge Dead Time t_dead = Qgd / Igate
- PFC Boost Inductor L = Vin² × (Vout − Vin) / (Vout × ΔI × f × Pout)
- Hold-Up Time Capacitor t = C × (Vmax² − Vmin²) / (2 × P)
- Switching Loss (Power Context) Psw = 0.5 × V × I × (tr + tf) × f
- Half-Wave Rectifier DC Output Vdc = Vpeak / π
- Full-Wave Rectifier DC Output Vdc = 2 · Vpeak / π
- Bridge Rectifier Peak Output Vdc = Vpeak − 2 · Vdiode
- Rectifier Ripple Factor r = √((Vrms/Vdc)² − 1)
- Rectifier Efficiency η = Pdc / Pac
- Peak Inverse Voltage (Centre-Tap) PIV = 2 · Vpeak
- Capacitive Dropper Supply Current I = 2π · f · C · Vrms
- Half-Wave Rectified RMS Voltage Vrms = Vpeak / 2
- Boost Inductor Value L = Vin·(Vout−Vin) / (ΔIL·fs·Vout)
- Boost Inductor Ripple Current ΔIL = Vin · D / (fs · L)
- Boost Peak Switch Current Ipk = Iout/(1−D) + ΔIL/2
- Boost Output Capacitor Cout = Iout · D / (fs · ΔVout)
- Buck Output Ripple (with ESR) ΔVout = ΔIL · (ESR + 1/(8·fs·Cout))
- Regulator Feedback Divider Vout = Vref · (1 + R1/R2)
- LDO Power Dissipation (with Iq) Pd = (Vin − Vout)·Iout + Vin·Iq
- LDO Efficiency (with Iq) η = Vout·Iout / (Vin·(Iout + Iq))
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