The bottom left rating says “10A 30VDC”, meaning the relay can switch a maximum current of 10A DC before the contacts get damaged. For example, the top left marking says “10A 250VAC”, which means the relay can switch a maximum load of 10A when connected to a 250V mains circuit. There are also voltage and current markings, which represent the maximum voltage and current, the relay can switch. The part number of the relay on the bottom says “05VDC”, which means that the relay coil is activated at 5V minimum – any voltage lower than this will not be able to reliably close the contacts of the relay. Lots of information can be gleaned from the markings on the relay itself. The second is the relay itself, which, in this case, is a blue plastic case.

Adding screw terminals makes it easier to connect thick mains cables, which might be difficult to solder directly. The three connections on the terminal block are connected to the normally open, normally closed, and common terminals of the relay. This is the part of the module that is in contact with mains so a reliable connection is needed. The single-channel relay module is much more than just a plain relay, it contains components that make switching and connection easier and act as indicators to show if the module is powered and if the relay is active.įirst is the screw terminal block. Understanding 5V Single-Channel Relay Module The following are the major components present on a relay module we will get into the details later in this article.ĥV Relay, Transistor, Diode, LEDs, Resistors, Male Header pins, 3-pin screw-type terminal connector, etc. Relay maximum contact voltage – 250VAC or 30VDCĭual-channel relay module, four-channel relay module, 8-channel relay module.Ĭomponents Present on a 5V Single Channel Relay Module.Current when the relay is active: ~70mA.Single-Channel Relay Module Specifications Single-Channel Relay Module Pin Description Relay is an electromechanical device that uses an electric current to open or close the contacts of a switch. The single-channel relay module is much more than just a plain relay, it comprises of components that make switching and connection easier and act as indicators to show if the module is powered and if the relay is active or not.

Arduino relay schematic