🔌 Linear Power Supply Designer

🎯 Getting Started

This tool helps you design complete linear power supplies by calculating:

• Filter Capacitor Size: Based on desired ripple voltage and load current
• Rectifier Selection: Half-wave, full-wave center-tap, or bridge
• Diode PIV Requirements: Peak Inverse Voltage ratings for your rectifier
• Voltage Regulator: Common 78xx/79xx series regulators

🔄 Rectifier Types

Half-Wave: Single diode rectifier. Simple but inefficient.

• Frequency: Same as input (50/60Hz)
• PIV Rating: 1× Peak Voltage
• Output: Lower DC voltage, higher ripple

Full-Wave (Center-Tap): Two diodes with center-tapped transformer.

• Frequency: 2× input (100/120Hz)
• PIV Rating: 2× Peak Voltage
• Output: Better efficiency, requires special transformer

Bridge Rectifier: Four diodes in bridge configuration.

• Frequency: 2× input (100/120Hz)
• PIV Rating: 1× Peak Voltage
• Output: Most common, efficient, standard transformer

📐 Ripple Voltage Formula

V_ripple = I_load / (f × C)

• V_ripple = Peak-to-peak ripple voltage (V)
• I_load = Load current (A)
• f = Ripple frequency (Hz) - depends on rectifier type
• C = Filter capacitor (F)

Lower ripple requires larger capacitors. Typical ripple is 1-10% of DC output.

⚡ Voltage Regulators

78xx Series (Positive): 7805 (5V), 7809 (9V), 7812 (12V), 7815 (15V), 7824 (24V)

79xx Series (Negative): 7905 (-5V), 7912 (-12V), 7915 (-15V)

Dropout Voltage: Regulators need ~2-3V headroom above output voltage. Input voltage must be higher than output + dropout.

💡 Design Tips

• Use bridge rectifiers for most applications (efficient, standard transformers)
• Target 1-2V ripple for regulated supplies (regulator filters remaining ripple)
• For unregulated supplies, aim for <5% ripple (0.5V for 10V output)
• Add safety margin: choose diodes with PIV rating 1.5-2× calculated value
• Electrolytic capacitors: higher voltage rating is safer (use 1.5-2× DC voltage)