12V 2-Channel Relay Module with Optocoupler Isolation 10A 250VAC

Specifications:

• Operating Voltage: 12V DC
  
• Channels: 2 Independent Channels
  
• Load Capacity: 10A  250VAC / 10A  30VDC
  
• Isolation: Optocoupler (PC817) for signal safety
  
• Trigger Logic: Adjustable High/Low Level Trigger (via Jumper)
  
• Indicators: Power LED (Green), Relay Status LEDs (Red)
  
• Interface: Standard screw terminals for load; Male headers for control signals

Applications:

• Home Automation: Control two separate room lights or a ceiling fan.
  
• Industrial Controls: Switch solenoids, valves, or high-power contactors.
  
• Automotive Projects: Control 12V fog lights or horns using logic signals.
  
• Garden Automation: Manage water pumps and solenoid valves for irrigation.

Project Evolution

• Prerequisites (The Foundation): If you have mastered blinking an LED or controlling a small 5V relay, you understand the basics of digital switching.
• Experience Level: Beginner to Intermediate.
• The Upgrade (What This Module Unlocks): This 12V module allows you to step up to Industrial & Automotive voltages. Unlike 5V modules, this integrates perfectly into 12V systems (like cars or solar setups) without needing voltage buck converters for the relay coils. You can now build a Dual-Zone Climate Controller or a Wifi-Controlled Garage Door Opener.
• Effort & Requirements:
• Effort: Intermediate (Requires careful high-voltage wiring).
• Hardware: Requires a 12V DC Power Source and a Microcontroller (Arduino/ESP32).

Virtual Technician: Wiring & Safety

⚠️ DANGER: Working with 220V AC mains is dangerous. Always disconnect power before touching wiring.

Pinout Guide:

• DC+: Connect to 12V Positive.
  
• DC-: Connect to Ground (GND).
  
• IN1 / IN2: Control Signal (Connect to Microcontroller Pin).

JD-VCC Jumper Note: For complete isolation, remove the jumper cap. Connect the relay power (12V) to JD-VCC and GND, and your microcontroller's 5V/3.3V logic power to VCC.

Package Including : 1 X 12V 2-Channel Relay Module with Optocoupler Isolation (10A 250VAC)

Frequently Asked Questions (FAQ)

1. Does this relay module work with 3.3V ESP32 logic?
   Yes, the optocoupler inputs are sensitive enough to be triggered by 3.3V logic signals from ESP32 or Raspberry Pi.
2. Can I control a ceiling fan with this?
   Yes, as long as the fan's current draw is under 10A. Most ceiling fans draw far less (approx 0.3A), so it is safe.
3. Do I need an external 12V power supply?
   Yes, the relay coils require 12V DC to energize. Your microcontroller (Arduino) cannot power the coils directly.
4. What does the Jumper cap do?
   The jumper selects between High-Level Trigger (relay ON when signal is HIGH) and Low-Level Trigger (relay ON when signal is LOW).
5. Is this module Active Low or Active High?
   It is configurable. You can change the trigger mode using the onboard jumper for each channel.
6. Can I switch DC loads like a motor?
   Yes, the relay can switch DC loads up to 30V DC at 10A.
7. Why is my relay clicking but the light isn't turning on?
   Check your wiring at the COM (Common) and NO (Normally Open) terminals. Ensure the AC live wire is cut and looped through these two.
8. What is the "Optocoupler" for?
   It isolates your microcontroller from the relay circuit using light, preventing noise and voltage spikes from damaging your board.
9. Can I use this with a Raspberry Pi?
   Yes, connect the Pi's GPIO to IN1/IN2. Ensure you have a separate 12V supply for the relay board (DC+/DC-).
10. What is the difference between this and a Solid State Relay (SSR)?
    This mechanical relay creates a physical break in the circuit and can handle AC/DC. SSRs are silent and faster but generate heat and usually only handle AC.
11. Does it have flyback diode protection?
    Yes, the module includes protection diodes to prevent back EMF from the relay coils damaging the circuit.
12. Can I control both channels simultaneously?
    Yes, IN1 and IN2 are independent. You can turn them on/off individually or together.
13. What is the "COM" terminal?
    COM stands for Common. It is the center pin of the output terminal block where you connect your power source line.
14. What are NO and NC?
    NO (Normally Open) connects to COM when the relay is ON. NC (Normally Closed) connects to COM when the relay is OFF.
15. How much current does the input pin draw?
    The input signal pin draws very little current (approx 5-20mA), safe for any standard microcontroller GPIO.
16. Why are there 3 pins on the output side?
    The 3 pins are NO, COM, and NC, allowing you to choose whether the device is default ON or default OFF.
17. Can I mount this on a DIN rail?
    The board has mounting holes but no DIN rail clip. You will need a separate PCB carrier or PCB feet.
18. Is this waterproof?
    No, this is an open PCB module. It must be placed inside an enclosure for outdoor use.
19. Will this work with a 9V battery?
    Likely not reliably. 12V relays usually require at least 10-11V to engage the coil properly.
20. Can I use PWM to dim lights with this?
    No, mechanical relays cannot switch fast enough for PWM dimming. You need a TRIAC or MOSFET module for that.