Switching module are simply circuit boards that house one or more relays. They come in a variety of shapes and sizes but are most commonly rectangular with 2, 4, or 8 relays mounted on them, sometimes even up to 16 relays. Relay modules are fundamental components in electronics, acting as electrical switches that can be controlled by low-power signals to manage high-power circuits. Its main purpose is to safeguard electrical equipment like transformers, generators, and transmission lines from damage due to. What is a Relay Module? Source: https://en. It allows a low-voltage signal (e. Protective relays detect defective lines, defective apparatuses, or other power system conditions of an abnormal or dangerous nature.