The Problem :

In Power over Ethernet (PoE) systems, reverse voltage can be a silent killer. When the voltage polarity is reversed, it can damage sensitive components, including your PoE injector, switches, or powered devices. This can happen easily when cables are swapped or misconnected—leading to costly repairs or replacements. But the good news? Reverse voltage protection is simple to implement!

The Solution :

To protect against reverse voltage, you can use diodes in the power path. Diodes only allow current to flow in one direction, blocking any reverse polarity from reaching your PoE device. Simply place a diode in series with the power line to ensure correct polarity. If the power is connected in reverse, the diode will block it, preventing damage to your equipment.

Practical Example :

Imagine you’re building a PoE-enabled camera system. After wiring everything, you accidentally connect the power source with reversed polarity. Without protection, the camera’s internal components could be damaged. By adding a diode, you can safeguard the camera from reverse voltage and avoid the hassle of replacing it.

Sample Calculation :

Let’s say you’re using a 12V PoE system and need to calculate the resistor value for current limiting.

If your current is 1A, and you want to drop 0.7V (diode’s forward voltage), use Ohm’s Law:

R = V/I = 0.7V / 1A = 0.7 ohms.

Shop Now :

Protect your PoE systems with quality components. Get diodes and resistors Made in India at SmartXProKits! Shop now: Diodes for PoE Protection.

Support our work and India’s innovation—buy from our Make in India site!