🔧 The Problem :

In embedded systems or DIY projects, reverse current can damage delicate display modules (like OLEDs or LCDs), especially when using multiple power sources. If current flows the wrong way—say, from a charged capacitor or another load—it can destroy your display.

✅ The Solution :

The fix is simple: use a P-channel MOSFET or a Schottky diode to block reverse current. Diodes are easy, but MOSFETs offer lower voltage drop and higher efficiency—perfect for battery-powered or low-voltage systems.

💡 Practical Example :

You’re powering a 5V OLED display from a USB supply. A second power rail at 3.3V accidentally stays on after USB disconnects. Without protection, the 3.3V may backfeed and fry your OLED. A MOSFET between the 5V rail and display blocks reverse flow safely.

📐 Sample Calculation :

Using a Schottky diode with 0.3V forward drop:
If the display draws 100mA, power loss = P = V × I = 0.3V × 0.1A = 30mW
Using a P-channel MOSFET (Rds(on) ≈ 0.05Ω):
Power loss = P = I² × R = 0.01 × 0.05 = 0.5mW → much more efficient!

🛠️ Product Suggestion :

Grab a P-channel MOSFET or flux for clean soldering—Made in India for quality and reliability:

🔗 MOSFET

🔗 Flux

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