8-Channel Relay Module 5V — 10A SPDT, Active-Low, Opto-Isolated, Arduino Compatible

8-Channel Relay Module — 5V, 10A SPDT, Active-Low, Opto-Isolated

The 8-channel 5V relay module provides eight independently controlled SPDT relays on a single PCB — the standard solution for Arduino and ESP32 home automation projects requiring control of multiple AC or DC loads simultaneously. Each relay is driven by an onboard transistor and opto-isolator, requiring only <5mA from each GPIO pin to switch a 10A load. All eight relays can be energized simultaneously, drawing ~600mA total from the 5V supply.

The JD-VCC jumper allows the module to operate in two modes: standard mode (jumper installed, single 5V supply) or fully opto-isolated mode (jumper removed, separate 5V supply for relay coils) for maximum protection against AC-side faults.

Key Features

• 8 independently controlled SPDT relays — IN1–IN8, each independently addressable
• 10A SPDT contacts — switches up to 250VAC @ 10A or 15VDC @ 10A per channel
• Active-LOW control — logic LOW energizes relay; logic HIGH de-energizes
• Opto-isolated inputs — complete electrical isolation between MCU and relay power
• JD-VCC jumper — selectable single-supply or dual-supply (full isolation) mode
• <5mA GPIO drive — safe for all Arduino, ESP32, and Raspberry Pi GPIO pins
• Red LED indicators — one per channel, illuminates when relay energized
• Built-in flyback diodes — protects driver transistors from relay coil back-EMF
• 4 × M3 mounting holes — for secure enclosure mounting

Technical Specifications

Supply Voltage	5V DC
Supply Current	~70mA per relay energized (~600mA all 8 on)
Control Logic	Active-LOW (LOW = relay ON)
Logic HIGH threshold	>2.8V
Logic LOW threshold	<1.2V
GPIO Current Required	<5mA (opto-isolated driver onboard)
Relay Contact Rating (AC)	115VAC @ 10A / 250VAC @ 10A
Relay Contact Rating (DC)	15V DC @ 10A (recommended max)
Relay Type	SPDT (NO + NC + COM) per channel
PCB Dimensions	138 × 56 × 20mm (5.4 × 2.2 × 0.79″)

Wiring Guide

Control header (1×10):

• GND → Arduino/MCU GND (must share ground)
• IN1–IN8 → Arduino digital output pins (LOW = relay ON)
• VCC → 5V supply

Isolation header (1×3):

• JD-VCC → Relay coil power. Jumper to VCC for single-supply mode (default). Remove jumper, connect separate 5V for full opto-isolation.
• VCC → Logic supply (same as control header VCC)
• GND → Ground for separate relay supply (if used)

Load screw terminals (per channel): NO / COM / NC — same as 1-channel module.

Opto-Isolation Modes

• Standard mode (jumper installed): JD-VCC tied to VCC — single 5V supply powers both logic and relay coils. Opto-isolators still present but not providing full isolation. Easiest setup.
• Full isolation mode (jumper removed): Separate 5V supply connected to JD-VCC powers relay coils independently. MCU logic circuit is fully isolated from relay power — maximum protection against AC-side faults, lightning strikes, or load failures.

DC Voltage Limit

Relay contacts are rated 30VDC on the relay body, but DC arc suppression is poor above ~15V. Limit DC switching to 15V or below. AC performance is excellent — tested at 1500W / 12.5A heater load without issues.

Typical Applications

• Arduino / ESP32 home automation — control 8 lights, fans, or appliances from a single board
• Smart home relay controller — MQTT / Home Assistant / Node-RED integration
• Irrigation system — control 8 solenoid valves for zone-based watering
• Industrial PLC output expansion — 8-channel relay output card
• Greenhouse automation — lights, heaters, fans, misters, CO₂ valves
• 3D printer enclosure control — lights, exhaust fan, filament dryer
• Escape room and prop control — 8 independently triggered effects

Package Contents

• 1 × 8-Channel Relay Module 5V (10A SPDT, active-low, opto-isolated, with screw terminals)

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