1 Channel Relay Module 5V (Active Low) - Robocraze

1 Channel 5V Active Low Relay Board

The 1 channel relay module is a versatile and reliable switching solution designed for microcontroller projects and DIY electronics. Operating with a 5V TTL control signal, this 5V relay module features built-in optocoupler isolation, making it perfect for safely controlling high-voltage home automation appliances, motors, LED strips, and solenoid valves.

Acting like a regular switch, this single channel relay keeps its output contacts completely isolated from the control circuit. It provides easy wiring via standard NO, NC, and COM terminals, ensuring safe and stable operation up to 10A 250VAC. A built-in LED indicator clearly shows when the relay is active. It seamlessly accepts input from 3.3V to 5V microcontrollers, making it an ideal choice for any Arduino or ESP32 project.

Note: It is important that the microcontroller shares ground with the relay board along with other control signals else it will not be able to control the relay.

Not sure how to wire your setup? Read our complete guide on relay working principles and applications for step-by-step wiring examples.

Also, check the other 5V Relays Collections.

Check out our wide variety of Relays including 5V, 12V, and Solid state relay switches.

NO, NC, and COM Terminals Explained:

Understanding the output terminals is key to wiring your relay module safely. This single channel relay features three standard screw terminals for connecting your high-voltage load:

• COM (Common): This is the central terminal. You connect your load’s power source (e.g., the live wire of an AC appliance) to this pin.
• NO (Normally Open): In its default, inactive state, the connection between COM and NO is broken (open). When the relay is triggered, the switch closes, allowing current to flow. Best for: Turning devices ON with a signal, such as lights, water pumps, or motors.
• NC (Normally Closed): In its default state, the connection between COM and NC is complete (closed). When the relay is triggered, the switch opens, cutting off power. Best for: Safety circuits or devices you want to turn OFF when a signal is received, such as an alarm system or a cooling fan.

Active Low vs Active High Trigger

When selecting a 5V relay module, you will often see "Active Low" or "Active High" in the specifications. Here is the difference and why this module is designed the way it is:

• Active High: The relay triggers (switches the load) when the microcontroller sends a HIGH signal (e.g., 3.3V or 5V).
• Active Low: The relay triggers when the microcontroller pulls the input pin to LOW (0V / Ground).
  Why this module uses Active Low:

This is a deliberate design choice for safety and reliability. When microcontrollers like Arduino or ESP32 boot up or reset, their GPIO pins often default to a floating or HIGH state. If you used an active high relay, your connected appliances (like a heater or motor) could accidentally turn on during startup. With this active low relay module, the circuit remains safely open during boot, and the relay will only activate when your code explicitly pulls the pin LOW.

Looking for the Best Price for a 1 Channel 5V Relay Module Online?

At Robocraze, the price starts at just ₹29, making it one of the most affordable and reliable options for makers, students, and IoT developers. Prices may vary depending on ongoing offers, brand selection, and stock availability. Unlike many low-grade alternatives in the market, our relay modules undergo strict quality checks to ensure stable switching performance, durable PCB design, and long operational life. Whether you're building home automation systems, robotics projects, or industrial prototypes, we provide genuine components that deliver better reliability and performance compared to unverified marketplace sellers.

Features:

• Input signal can come directly from a microcontroller
• Works at 3V or 5V to control relays
• Can switch a variety of AC or DC high voltage loads
• Suitable for SCM development and home appliance control
• 5V~12V TTL control signal for DC/AC control
• LED indication of relay ON
• Contact rating: 5A at 240V AC
• Direct input from 3-5V microcontroller for relay control
• Provision of 2x3Pin male header for wire connection
• Powered from external 5V or from the male header
• Relay contact is isolated from the driven circuit

Applications:

• Home automation
• Robotics
• Light control
• Motor control
• Solenoid control
• Valve control
• Process control
• Alarm systems
• Access control systems
• Surveillance systems
• DIY projects

Pinout:

1 Channel 5V Relay Module Specifications Comparison: