4-Channel Solid State Relay Module (DC to AC Control) – 5V/12V/24V Trigger, High/Low Level Selectable

SKU: FA2084-1
Channels

4
Control Voltage (Input)

5V / 12V / 24V DC (Jumper Selectable)
Trigger Mode

High-Level or Low-Level (Jumper Selectable)
Load Voltage (Output)

24 ~ 240V AC
Maximum Load Current

2A per channel
Isolation Voltage

2500V RMS
Switching Function

Zero-Crossing
On-state Resistance

< 30mΩ
Dimensions

Approx. 100mm x 80mm x 25mm

Product Description

The 4-Channel Solid State Relay (SSR) Module is a sophisticated, fully-isolated switching solution designed for silent, reliable, and long-lasting control of AC loads using low-voltage DC signals. Engineered to offer maximum flexibility, it supports a wide 5V/12V/24V DC control voltage range and features selectable high/low-level trigger logic, making it universally compatible with virtually any microcontroller, PLC, or digital controller on the market. This module is the modern, solid-state alternative to traditional electromagnetic relays, eliminating moving parts for completely silent operation, faster switching, and exceptional longevity—ideal for noise-sensitive environments and high-cycle applications.
Each channel provides robust 2500V optical isolation, ensuring your sensitive control electronics are completely protected from high-voltage AC transients and noise. The integrated zero-crossing detection circuit switches the load precisely as the AC waveform crosses zero volts, dramatically reducing electromagnetic interference (EMI) and inrush current to protect both the relay and connected devices like motors, heaters, and lamps. With its clear status LEDs, versatile control options, and reliable screw terminal connections, this module is the perfect choice for advanced home automation, professional industrial control systems, and robust IoT applications requiring safe and precise AC power management.

Key Features

  • Universal Control Voltage:​ Jumper-selectable 5V, 12V, or 24V DC input makes it compatible with Arduino, Raspberry Pi, PLCs, and 12V/24V industrial systems without modification.
  • Selectable Trigger Logic:​ Choose between High-Level or Low-Level trigger for each channel via onboard jumpers, offering perfect compatibility with any control logic (sourcing or sinking).
  • Full Optical Isolation:​ Advanced optocoupler isolation (2500Vrms) on each channel provides complete electrical separation between your low-voltage DC control circuit and the high-voltage AC load, ensuring safety and noise immunity.
  • Zero-Crossing Switching:​ Built-in zero-crossing circuitry minimizes EMI/RFI noise and prevents high inrush current, protecting both the SSR and connected devices for extended operational life.
  • Four Independent AC Outputs:​ Control up to four separate AC appliances or circuits independently with a single, compact module.
  • Silent & Maintenance-Free Operation:​ Solid-state design with no moving parts or contacts to wear out, ensuring silent switching and a vastly longer lifespan than mechanical relays.
  • Clear Visual Status:​ Bright LED indicators for each channel provide instant visual feedback of the switching state.
  • Secure & Safe Connections:​ High-quality screw terminals for both control and load wiring ensure reliable, vibration-resistant connections for safety and performance.

Main Parameters

  • Channels:​ 4
  • Control Voltage (Input):​ 5V / 12V / 24V DC (Jumper Selectable)
  • Trigger Mode:​ High-Level or Low-Level (Jumper Selectable)
  • Load Voltage (Output):​ 24 ~ 240V AC
  • Maximum Load Current:​ 2A per channel
  • Isolation Voltage:​ 2500V RMS
  • Switching Function:​ Zero-Crossing
  • On-state Resistance:​ < 30mΩ
  • Dimensions:​ Approx. 100mm x 80mm x 25mm

Typical Applications / Usage

  1. Smart Home Automation Hub:​ Seamlessly integrate and control multiple AC appliances (lamps, fans, coffee makers) via a central microcontroller, Wi-Fi, or Bluetooth.
  2. Industrial Control & PLC Interfacing:​ A reliable and isolated output module for Programmable Logic Controllers (PLCs) to safely control solenoids, contactor coils, and small motor starters in factory automation.
  3. HVAC & Environmental Control:​ Manage heaters, humidifiers, and ventilation fans in greenhouses, server rooms, or home climate control systems with precise, silent switching.
  4. IoT & Remote Control Projects:​ Build custom Internet-of-Things controllers for remotely managing AC devices, thanks to the module’s silent operation and compatibility with popular development boards.
  5. Stage & Lighting Control:​ Perfect for DIY and small-scale professional lighting systems where silent operation and reliable, flicker-free switching are essential.
  6. Energy Management Systems:​ Integrate into systems that schedule or remotely switch AC loads to optimize power consumption.
Implementation Guide:
  • Configuration:​ First, set the VCC Jumper​ to match your control board’s voltage (5V, 12V, or 24V). Then, set the Trigger Jumper​ for each channel to either “H” (activates on HIGH signal) or “L” (activates on LOW signal).
  • Control Wiring:​ Connect the module’s VCC​ and GND​ to your chosen DC power supply. Connect the signal pins (IN1-IN4) to the digital output pins of your controller (e.g., Arduino, PLC output).
  • Load Wiring:​ Connect the AC “Hot” wire (e.g., 120VAC Line) to the relay’s COM​ terminal. Connect the device you wish to control between the relay’s NO​ (Normally Open) terminal and the AC “Neutral” wire. CRITICAL:​ Always ensure all AC mains power is DISCONNECTED​ and verified with a meter before making any wiring connections. Follow all local electrical codes.
Q: What is the main advantage of a Solid State Relay (SSR) over a regular relay?

SSRs have no moving parts, which means they operate silently, switch much faster, have an extremely long lifespan (billions of cycles vs. millions for mechanical relays), and do not suffer from contact arcing or bouncing. They are ideal for applications requiring frequent switching or where audible noise is undesirable.

Q: Can I use this module to control DC loads, like a 12V DC fan?

No, you cannot.​ This specific SSR module is designed exclusively for AC output. The internal thyristor/TRIAC requires the AC waveform to naturally drop to zero to turn off. For switching DC loads, you must use a DC-output SSR.

Q: How do I choose between High-Level and Low-Level trigger?

It depends on your controller’s default logic. Most microcontrollers (like Arduino) are “active-HIGH” (pin goes HIGH to activate). For these, use High-Level trigger. Some PLCs or systems use “sinking” logic (pin goes LOW/0V to activate). For those, use Low-Level trigger. The jumper lets you match the module to your system.

Q: My control signal is 3.3V (like ESP32). Can I use the 5V setting?

Often, yes. While the module’s power(VCC) should be 5V, the 3.3V logic HIGH from an ESP32 is usually sufficient to trigger the optocoupler when the trigger jumper is set to “H”. For guaranteed operation, check if your 3.3V controller is 5V-tolerant on its outputs or use a simple logic level shifter.

Q: What is "Zero-Crossing," and are there any downsides?

Zero-crossing turns the load on/off only when the AC voltage sine wave passes through 0V. This drastically reduces electrical noise and stress on the load. The only downside is a tiny delay (max half a cycle, or ~10ms at 50Hz) before switching occurs, making it unsuitable for phase-angle control​ applications like light dimming.

Q: Can I use this to control a large appliance like a water heater (3000W)?

Absolutely not.​ This module is rated for 2A per channel. At 240VAC, that’s a maximum of 480W. Exceeding the current rating will destroy the SSR. To control high-power appliances, use this SSR module to drive the coil of a higher-rated contactor, which then switches the main load.

Q: Do I need a heatsink?

It depends on the load. For small loads (<0.5A) or intermittent use, a heatsink is not required. For continuous operation near the 2A maximum, mounting the SSR module on an aluminum heatsink​ is strongly recommended​ to dissipate heat and ensure reliability.

Q: Is this suitable for business and industrial OEM integration?
Yes, perfectly.​ Its industrial-grade components, optical isolation, flexible voltage input, and robust construction make it an excellent, reliable choice for integration into commercial products, industrial control panels, and OEM equipment. We offer volume pricing, custom branding, and technical support for business and industrial clients.

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