In HVAC systems, reverse current can damage sensitive components when power flows the wrong way—usually during power loss or generator switchover. For electronics hobbyists and engineers in India, protecting circuits from this is essential, and fortunately, it’s easy to do.

🔧 The Problem: Current Flowing Backwards

When two power sources (like a battery backup and mains) are connected, current can accidentally flow from one to the other. This “reverse current” can overheat components or drain power sources unnecessarily—especially in control boards and motor drives.

✅ The Solution: Add Reverse Current Protection

The easiest fix is using Schottky diodes or P-channel MOSFETs. Diodes block reverse current flow, while MOSFETs offer lower voltage drop and better efficiency—perfect for HVAC loads.

🔍 Practical Example: HVAC Control Unit

You’ve built a custom control unit for an HVAC fan that runs on both grid and solar power. During switchover, your circuit gets hot. You add a P-channel MOSFET in the power line with the source to VIN and the gate tied low. It only allows current in the right direction, saving your board!

🧮 Sample Calculation: Diode Voltage Drop

Typical Schottky diode: Vf = 0.3V
Load current = 2A
Power loss = Vf × I = 0.3 × 2 = 0.6W

Switching to a MOSFET with 20mΩ Rds(on):
P = I²R = 2² × 0.02 = 0.08W → Much more efficient!

🛒 Product Suggestion: Made in India Components

• 🛡️ [Shop Schottky diodes]

• ⚙️ [Shop P-channel MOSFETs]

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