The Problem :

When working with DC circuits, reverse current can damage sensitive components by allowing current to flow in the wrong direction. This often happens when power supplies or batteries are connected backward. Fortunately, reverse current protection using relays is a simple and effective fix.

The Solution :

A relay acts as an automatic switch that disconnects the circuit if the polarity is reversed. When the voltage is correctly applied, the relay energizes and allows current to flow through. If the polarity is incorrect, the relay remains off, preventing reverse current from damaging the load.

Practical Example :

Consider a battery-powered motor. If the battery is accidentally connected backward, it may burn out the motor or damage the circuit. By placing a relay in series with the power supply, you ensure that the motor only receives power when the polarity is correct.

Sample Calculation :

If you’re using a 12V relay with a coil resistance of 120 ohms, the current drawn by the coil can be calculated as:

I=RV​=12012​=0.1A

This helps you choose an appropriate power supply that can handle the relay’s load.

Recommended Components :

To implement this solution, consider using a 12V SPDT relay and a diode for extra protection. Check out our selection of Made in India components:

• 12V relay

• Diodes for protection

Protect your circuits with reliable, Made in India relays and diodes.

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