This module can be used to switch a 230V AC load. It is sold on major chinese marketplaces. The module contains an ultra bright SMD LED which indicates if a 5V Signal is present. It also contains a flywheel diode for the inductor to reduce voltage spikes when the inductor is switched on or off. Although this module is often used with Arduinos, it needs a powerful +5V supply, which the 5V output pin of an Arduino can't supply.
