Wiring a DC motor incorrectly—especially in DIY or prototyping stages—can instantly damage your driver circuit or burn out the motor. That’s why reverse polarity protection is a must in every motor-based design.

The Problem: Accidental Reverse Connections

DC motors are often powered by battery packs or external power supplies. Connecting the power lines in reverse can cause:

• Motor controller damage

• MOSFET burnout

• Permanent component failure

The Solution: Use a Diode or P-Channel MOSFET

For basic protection:

• Use a Schottky diode in series with the supply to block reverse voltage

• For better efficiency, use a P-Channel MOSFET with its source to the positive rail and gate to ground. It conducts normally when voltage is correct and blocks reverse input.

Practical Example: 12V DC Motor with L298N

If a hobbyist connects the power adapter in reverse to a motor module like L298N, it can get fried.

Fix: Add a P-Channel MOSFET (e.g., IRF9540) at the power input. It blocks reverse polarity with minimal voltage drop.

Sample Calculation: Diode Drop Loss

With a 12V motor and 2A current:

Power loss = 0.6V × 2A = 1.2W (Schottky diode)

MOSFET drop < 0.1V → saves over 1W!

Product Suggestion (Made in India)

Build safer circuits with Indian-made essentials:

• P-Channel MOSFETs – Efficient reverse protection

• Flux Paste – Clean connections, better conductivity

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