This 5V 4 Channel SSR Solid State Relay Module 240V 2A Output with Resistive Fuse is based on the Omron G3MB SSR relay which can control up to 2A at 240VAC. This is a 4 Channel SSR relay module, each relay channel has 3 separate terminals, NO (Normal Open), COM (Common), NC (Normal Closed). A Solid State Relay is similar to a mechanic relay where it can be controlled through a digital signal. Solid State Relay generates no noise and has a much longer lifespan in compared to the traditional mechanic relay. When the input logic voltage is applied to the coil, the NC will disconnect from the COM breaking the conductivity between the two. At the same time, the NO will connect with the COM allowing conductivity between them. Depending on your wiring this will turn on or off the connected load. Note: Actual product may Input parts : DC : connect power positive DC-: connect power negative CH1: relay module signal trigger point (Effective low-level trigger) CH2: relay module signal trigger point (Effective low-level trigger) CH3: relay module signal trigger point (Effective low-level trigger) CH4: relay module signal trigger point (Effective low-level trigger) We are also selling the same product with the good built quality which slightly costs more than this product(note that the except quality there are no differences in both product), click below to check it out. 5V 4 Channel SSR Solid State Relay Module Features : Has been assembled, and the electrical test passed. Led indicator for each relay. Use it to control various appliances and other equipment with large current. It can be controlled directly by Microcontroller Input control signal voltage: 0-2.5V status low level, relay OFF 3-5V status high level, relay ON Package Includes : 1 x 5V 4 Channel SSR Solid State Relay Module SKU: PGI-0044448 Category: Relay