This is a 5V 1ch 30A relay interface board. It can be used to control a variety of high-current appliances and equipment. It has high-current relays that operate at a BIG current for 30A (250VAC/30VDC) and a standard interface that can be controlled directly by the microcontroller. optical isolators are built into the module. it keeps high voltage from affecting the system receiving the signal. it can work with a High/Low Trigger configured through a jumper.

Package Includes:

• 1 x 1 Channel 30A 5V with Optocoupler Active High and Low Trigger Relay Board

Features:

• 30A relay module, normally open interface maximum load: AC 250V/30A, DV 30V/30A.
• Optical coupling isolation, driving ability is strong, stable performance;
• trigger current is ~5mA.
• The module can be set to a high-level or low-level trigger by the jumper.
• Power indicator light (green), relay status indicator light (red).
• Module Size:50mm*33mm*24mm.

Description:

This is a 5V 1ch 30A relay interface board, It can be used to control a variety of high-current appliances and equipment. It has high-current relays with a standard interface that can be controlled directly by the microcontroller. optical isolators are built into the module. it keeps high voltage from affecting the system receiving the signal. An optocoupler is a component that uses light to transfer electrical signals between two states of isolation circuits while preventing high voltage from affecting the receiving system. The relay's maximum contact has a BIG current which is around 30A (250VAC/30VDC), and microcontrollers can be connected directly to the standard interface. Safety features are provided by red working status indicator lights. MCU control, industrial sector control, PLC control, and intelligent home control are all common applications. it can work with a High/Low Trigger configured through a jumper.

Principle of Work:

A relay is a type of switch that can be controlled with an electrical signal. It is a way to open or close a circuit in this case via a signal from the connected microcontroller. The relay isolates the circuit on the device you want to control from the device that's controlling it. and its High/Low Trigger configured through a jumper will allow the current to go through the power line when the control signal is VCC or High/GND or LOW when to change the jumper. optocoupler on the other hand makes real photo isolation between the relay and the MCU which is very good to minimize the distortion from the other side

Pinout of the Module: 

• DC+: DC power supply positive pole
• DC-: DC power supply negative pole
• IN: signal triggering pin
• JD+: relay control voltage positive
• JD-: relay control voltage negative
• DC+ and JD+ shorted by jumper cap, DC- and JD- shorted with jumper cap, it is the same voltage between trigger terminal and relay control terminal
• High and low-level trigger mode selection. The jumper and L pin connection, IN pin, is a low-level trigger upper and H pin connection, IN pin, is a high-level trigger
• Normally closed pin (NC): relay normally closed pin
• Common pin (COM): relay common pin
• Normally opened pin (NO): relay normally opened pin

Applications:

• Relay Drive from External Contacts.
• LED Series and Parallel Connections.
• Electronic Circuit Drive by Means of a Relay.
• Home automation
• Battery backup
• High current load switching

Circuit:

1 distinct load has been connected to the relay's NO terminals. the relay common terminal has a live wire connected to it. When the relay is activated, the load is powered and connected to the live wire. This configuration can be reversed by connecting the load to the NC terminal, which keeps the load powered on until the relay is activated. the relay is connected to pin 2 and the trigger in a high configeration.

Library:

This Module doesn't need a library to work.

Code:

void setup() {
 // initialize digital pin 2 as an output.
 pinMode(2, OUTPUT);



}
// the loop function runs over and over again forever
void loop() {
 digitalWrite(2, HIGH); // turn the LED ON by making the voltage HIGH delay(1000);
 delay(1000); // wait for a second 


 digitalWrite(2, LOW); // turn the on off(LOW is the voltage level)
 delay(1000); // wait for a second 

 
}

Technical Details:

• 1 Channel
• Voltage version: 5V/12V/24V
• The static current:5mA
• Working current:80mA
• Trigger current:2-4mA

Resources:

 Tutorial 1

Comparisons:

The Active High Triggered Relay Module is the easiest kind of relay board to work with it works as you expect it to work so when it's on the application on the other side of the relay is on (not like the Low Triggered Realy workers exactly the opposite) and the optocoupler gives you the advantage of easy connection which it doesn't need lots of thinking because the relay is latching in a separate way from your MCU using the phototransistor in it so it's easier than the relays with no optocouplers like this item (Relay Module Board 1 Channel 5V 10A Low-Level Trigger).

This kind of relay board has so many advantages like being able to withstand large inrush currents and high mechanical structure reliability, not being susceptible to the external electromagnetic environment, and being able to carry high voltage, and high current load but still, it has multiple disadvantages to the SSR Boards that they are slower than SSRs at 5 to 15ms and it has a larger package size, are not suitable for small projects and electromechanical relays tend to have a shorter life than other types of relays due to mechanical wear if you interested in SSRs you can get it from here