5V 4-Channel Relay Module with Optocoupler

Opto-isolated 4-channel relay board, 250VAC/10A per channel, for Arduino/ESP home-automation switching.

₹240 + 18% GST

SKU: BOTBIT-MOT-13 · Best for: DIY home automation to switch lights, fans and appliances

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Overview

About 5V 4-Channel Relay Module with Optocoupler.

The 5V 4-Channel Relay Module is the go-to board for switching mains-voltage appliances from a low-voltage microcontroller. Each of its four channels can switch loads up to 250VAC/10A or 30VDC/10A, letting you control lights, fans, pumps and other AC devices from an Arduino, ESP8266, ESP32 or Raspberry Pi.

The key safety feature is optocoupler isolation. Each input is opto-isolated, which electrically separates your delicate 5V logic from the relay coil and the mains side. This protects your microcontroller from voltage spikes and back-EMF, and it is the reason this board is preferred over cheaper non-isolated modules for home-automation builds.

At around Rs 240, this four-relay board is the most popular choice for DIY home automation, IoT switching and appliance control in India. It arrives ready to wire with screw terminals on the output side and a clean header block on the input side.

Key features

Why it stands out.

4 independent relay channels, each rated 250VAC/10A and 30VDC/10A

Optocoupler isolation on every input protects the microcontroller from the mains side

Screw-terminal outputs with NO, NC and COM contacts per channel

On-board status LEDs show which relays are energised

Active-low logic inputs work directly with 3.3V and 5V logic (Arduino, ESP, Pi)

Standard mounting holes for easy panel or enclosure fixing

Specifications

Selection facts.

Channels	4 relays
Board supply voltage	5V DC
Relay type	SPDT (NO / NC / COM)
AC switching rating	10A @ 250VAC per channel
DC switching rating	10A @ 30VDC per channel
Isolation	Optocoupler on each input
Trigger logic	Active LOW
Current per active relay	~60-70 mA
Indicators	Per-channel status LED + power LED
Jumper	VCC/JD-VCC jumper for common or separate coil supply

Applications

Where it is used.

DIY home automation to switch lights, fans and appliances
IoT relay control with ESP8266/ESP32 and Blynk/Home Assistant
Switching AC pumps, solenoid valves and motors
Automation of exhibition and hobby projects
Smart plug and appliance timer builds
Industrial-style on/off control from a microcontroller

Buying guide

How to choose.

Buy this 4-channel opto-isolated board if you need to switch multiple mains appliances safely from one microcontroller. The optocoupler isolation is the feature that matters most for mains work; do not substitute a non-isolated board for AC switching. If you only need one or two loads, single- or two-channel versions of the same board exist.

Check the trigger logic before wiring: these boards are usually active-LOW, meaning a channel turns ON when its input pin is pulled to GND. Keep this in mind so your relays do not switch ON at power-up before your firmware initialises the pins.

Pair it with a stable 5V supply capable of the coil current (all four relays on can draw ~250-300mA), an Arduino/ESP board, and proper insulated enclosure and wiring for the mains side. For the JD-VCC jumper, remove it and use a separate coil supply for maximum isolation.

FAQ

Common questions.

Does this board isolate my Arduino from the mains?

Yes. Each input channel is optocoupler-isolated, separating the 5V logic side from the relay coil and mains contacts. For full isolation, remove the VCC/JD-VCC jumper and power the coils from a separate 5V supply.

Is it active-high or active-low?

These modules are active-LOW by default: the relay energises when the input pin is driven LOW (to GND). Set your pins HIGH at startup to keep relays off until your code decides.

Can it work with a 3.3V ESP32 or ESP8266?

The board is powered by 5V, but the opto-isolated inputs trigger reliably from 3.3V logic, so ESP32, ESP8266 and Raspberry Pi GPIO can drive it. Provide 5V to the VCC pin for the relay coils.

What loads can each channel switch?

Each relay is rated up to 10A at 250VAC or 10A at 30VDC. Stay well below the rating for inductive loads like motors and pumps, and use the COM/NO/NC screw terminals for your load wiring.

Is it available in India and what is in the box?

Yes, it is widely available in India. You get the assembled 4-channel relay board itself; jumper wires and a power supply are not included and are bought separately.