As electronics enthusiasts, we’ve all been there: you connect a power supply to your circuit, but something goes wrong, and the device doesn’t work. A common culprit is reverse polarity — when the power supply is connected incorrectly, causing damage to sensitive components. But don’t worry, you can easily protect your circuits using a NMOS transistor!

The Problem :

Reverse polarity happens when you accidentally swap the positive and negative connections in your power supply. This can burn out components and cause permanent damage to your project.

The Solution :

The solution is reverse polarity protection. A simple way to implement this is by using an NMOS transistor. When the power is connected correctly, the NMOS transistor allows current to flow. If the polarity is reversed, the transistor blocks the current, preventing damage to your components.

Practical Example:

Imagine you’re powering a small LED circuit. Without reverse polarity protection, if the power supply is connected the wrong way, the LED might burn out. With an NMOS in place, the circuit will remain safe, as the NMOS transistor will block the current if the polarity is reversed.

Sample Calculation:

Let’s calculate the current-limiting resistor for your LED:

If your LED requires 20mA and your power supply is 5V:

Resistor = (5V – 2V) / 20mA = 150Ω.

Shop Now:

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