4 Channel 5V Solid State Relay (SSR) Module - 250V 2A Output - High Level Trigger with Resistive Fuse

Specifications:

• Relay Model: HFS4-2A-05DM
  
• Channels: 4 Independent Channels
  
• Control Input Voltage: 5V DC (Nominal)
  
• Trigger Type: High-Level Trigger (Logic 1 = ON)
  
• Switching Type: Zero-Cross Switching (Reduces Inrush Current)
  
• Rated Load Voltage: 100V to 240V AC (50/60Hz)
  
• Rated Load Current: 2 Amperes (Continuous per channel)
  
• Peak Current: 8 Amperes (Non-repetitive)
  
• Isolation: Phototriac (Optical Isolation)
  
• Protection: Built-in 2A Resistive Fuse per channel
  
• Quiescent Current: 0 mA (when all relays are off)
  
• Operating Current: ~12.5mA per channel when active

Key Applications

• Silent Home Automation: Control AC lights, fans, and small appliances without the loud clicking of mechanical relays.
  
• PID Temperature Control: High-speed switching makes this ideal for maintaining precise temperatures in heaters or ovens.
  
• Industrial Signal Multiplexing: Reliable switching for AC-powered solenoid valves and actuators in production lines.
  
• Museum & Stage Lighting: Perfectly silent operation for exhibits and theatrical control where background noise is prohibited.

Project Evolution

• Past Projects: If you have built basic "on/off" timers using mechanical relays, you have likely encountered contact pitting or noise issues.
  
• Feature Upgrade: Upgrading to this SSR module unlocks Silent PWM-like Control (Slow-PWM) for resistive loads, allowing for smoother power management without the fear of mechanical burnout.
  
• Effort/Requirements: Beginner Friendly. You only need basic GPIO knowledge and standard 5V power to get started.

Virtual Technician & Wiring

• VCC: Connect to 5V DC.
  
• GND: Connect to System Ground.
  
• CH1 - CH4: Connect to your Microcontroller GPIO (High = Relay Active).
  
• Load Side (A/B): Connect in series with your AC Load.
  
• ⚠️ SAFETY WARNING: This module switches AC HIGH VOLTAGE ONLY. It will not work for DC loads (e.g., 12V DC Motors). Always ensure the AC power is disconnected before wiring.

Package Includes: 

1 x 4 Channel 5V Solid State Relay (SSR) Module - 250V 2A Output - High Level Trigger with Resistive Fuse

Frequently Asked Questions (FAQ)

1. Can I use this to control a DC motor?
   No, SSRs based on triacs only work with AC loads.
2. Does this module require a separate power supply?
   It requires a stable 5V DC supply for the logic and relay coils.
3. What happens if I use a 3.3V signal?
   The module is Logic-Safe and will generally trigger at 3.3V, but a logic shifter is recommended for 100% reliability.
4. Is there a fuse on this board?
   Yes, each channel includes a 2A resistive fuse for short-circuit protection.
5. Does it make any noise?
   No, it is 100% silent during operation.
6. Can I control a 1/2 HP AC motor?
   No, the 2A rating is for resistive loads. Motors (inductive) have high inrush current; keep loads below 0.5A for motors.
7. What is a High-Level Trigger?
   The relay turns ON when the control pin receives a High (5V) signal and OFF when it receives 0V.
8. Can I use this for dimming lights?
   Not directly with standard PWM. It uses Zero-Cross switching which is better for ON/OFF or PID control.
9. What is Zero-Cross switching?
   It waits for the AC wave to hit zero volts before switching, which prevents electrical noise.
10. How many relays can I turn on at once?
    All 4 can be on simultaneously if your power supply provides at least 60mA.
11. Do I need a heatsink?
    At 2A continuous, no heatsink is required for the HFS4-2A-05DM.
12. Is this compatible with Raspberry Pi?
    Yes, the high-level trigger is compatible with Pi GPIOs.
13. Can it switch 110V AC?
    Yes, it is rated for 100V to 240V AC.
14. What is the resistive fuse for?
    It protects the relay and PCB traces in case of an overcurrent event on the load side.
15. Is it faster than a mechanical relay?
    Yes, switching time is approx. 1ms compared to 10ms for mechanical.
16. Why are SSRs more expensive?
    They use semiconductor technology which offers infinite cycles and silence, unlike mechanical parts.
17. Can I use this with ESP8266?
    Yes, it works well with ESP8266 logic levels.
18. What is the maximum voltage for the load?
    264V AC peak.
19. What is the minimum load current?
    SSRs require a small leakage current (approx 0.1A) to function correctly.
20. Is this board RoHS compliant?
    Yes, our ProMax series is fully compliant