SSR-40DA 40A Solid State Relay Module DC-AC Single Phase

SSR-40DA Solid State Relay – 40A Contactless DC-to-AC Load Control Module

The SSR-40DA is a high-performance single-phase solid state relay (SSR) designed for precise, contactless switching between a low-voltage DC control signal (3–32V DC) and an AC load circuit (24–380V AC). With a 40A current capacity, this module is ideal for industrial automation, DIY electronics, temperature controllers, and commercial electrical systems where reliable, long-lasting switching is essential.

Made in China.

Key Features

• Contactless DC-to-AC Switching: Controls 24–380V AC output using just a 3–32V DC input signal. The semiconductor switching design eliminates mechanical contact wear, extending service life more than 10× compared to traditional mechanical relays.
• Flame-Retardant ABS Shell: Reinforced, flame-resistant ABS housing formed under high-temperature processing effectively resists combustion under short-circuit or overheating conditions — enhancing safety in demanding, high-load environments.
• High-Conductivity Nickel-Plated Copper Terminals: High-purity nickel-plated copper connection terminals with anti-loosening screw fastening minimize power loss during current transmission and maintain a stable, firm connection under long-term vibration or heavy-load conditions.
• Reliable 40A Load Capacity: Optimized internal circuit design with built-in over-current protection supports 10–40A continuous current loads, making it suitable for a wide range of small and medium-power electrical equipment.
• Compact & DIY-Friendly: Compact 58 × 45 × 26 mm form factor fits neatly into enclosures, control panels, and DIY project builds.

Specifications

What's in the Box

• 1 × SSR-40DA Solid State Relay Module

Common Applications

• PID temperature controllers and heating element control
• Industrial automation and process control panels
• Arduino / Raspberry Pi / microcontroller-based DIY projects
• Motor speed controllers and lighting dimmer systems
• HVAC and commercial electrical load switching

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Frequently Asked Questions

Q: What is the input voltage range for the SSR-40DA solid state relay?

A: The SSR-40DA accepts a DC control input voltage of 3–32V, making it compatible with common microcontrollers (Arduino, Raspberry Pi), PLCs, and standard DC control signals. No additional driver circuit is required for most applications.

Q: What AC load voltage and current can the SSR-40DA handle?

A: This solid state relay module supports an AC load voltage range of 24–380V AC with a continuous current rating of 10–40A. It is suitable for controlling most small to medium-power single-phase AC equipment, including heaters, motors, and lighting systems.

Q: Does the SSR-40DA require a heat sink?

A: For continuous high-current operation (near 40A), attaching an external heat sink to the module's metal base plate is strongly recommended to prevent thermal build-up and ensure long-term reliability. For lower-load or intermittent switching applications, the module can operate without an additional heat sink.

Q: Is the SSR-40DA suitable for DIY and hobbyist electronics projects?

A: Yes. Its compact 58 × 45 × 26 mm footprint, screw-terminal connections, and wide DC input range make it very easy to integrate into DIY control panels, 3D printer heated beds, temperature control builds, and similar projects.

Production & Packaging Notice

To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.