DC 3V/3.3V Optocoupler Relay Module – Isolated Drive Control Board Take full control of your electronics projects with the ALLOYSEED DC 3V/3.3V Isolated Drive Control Board Relay Module. Designed for makers, hobbyists, and engineers, this compact optocoupler relay module delivers fast, reliable signal switching with built-in optical isolation — keeping your microcontroller safe while driving high-power loads. Compatible with Arduino, Raspberry Pi, ESP8266, and virtually any MCU platform, it's the dependable switching solution your automation projects demand. Made in Mainland China. Key Features Output Signal Indicator LED: Instantly confirm relay status at a glance — no guesswork required during testing or deployment. MCU-Compatible High-Level Trigger: Signal input connects directly to any microcontroller I/O pin. Supports 3V and 3.3V logic levels for seamless integration. Dual Power Supply Design: Independent control and load power supplies deliver strong anti-interference performance and rock-solid optical isolation, protecting your MCU from voltage spikes. Diode Reverse-Current Protection: Built-in flyback diode guards against reverse EMF, protecting both the relay coil and your circuit from damage. Fast Response & Long Service Life: Response time under 20ms and rated for up to 100,000 switching cycles — ideal for continuous automation and control applications. High Load Capacity: Capable of controlling loads up to 10A @ 250VAC or 10A @ 30VDC — suitable for lighting, motors, solenoids, and more. Specifications Brand ALLOYSEED Operating Voltage DC 3V / 3.3V Main Components EL817 Optocoupler, SRD-DC03V-SL-C Relay Max Load (AC) 10A @ 250VAC Max Load (DC) 10A @ 30VDC Response Time < 20ms Relay Lifespan 100,000+ operations Trigger Type High-level trigger Dimensions 70 × 20 × 17mm (2.76 × 0.79 × 0.67 in) Weight 20g Country of Origin Mainland China What's in the Box 1× DC 3V/3.3V Isolated Drive Control Board Relay Module Perfect For Arduino, Raspberry Pi, ESP8266/ESP32 automation projects Home automation and smart device switching Industrial control and signal isolation circuits Motor, lighting, and solenoid valve control DIY electronics prototyping and robotics Looking for more electronics accessories? Check out our 10-Pack 22AWG Glass Tube Fuse Holder Set and our 100W Dual-Port Fast Car Charger for more reliable power and circuit protection solutions. For technical standards and electrical safety guidance, refer to the U.S. Consumer Product Safety Commission – Electrical Safety resources. Frequently Asked Questions Q: Is this optocoupler relay module compatible with Arduino and Raspberry Pi? A: Yes! The DC 3V/3.3V relay module is fully compatible with Arduino, Raspberry Pi, ESP8266, ESP32, and any other microcontroller that outputs a 3V or 3.3V high-level signal on its I/O pins. Simply connect the signal pin from your MCU to the module's input and it will trigger reliably every time. Q: What is the maximum load this relay module can switch? A: This isolated relay module can handle loads up to 10A at 250VAC or 10A at 30VDC, making it suitable for controlling household lighting, small motors, solenoid valves, and other moderate-power devices safely from a low-voltage microcontroller signal. Q: Why does this relay module use optical isolation (optocoupler)? A: The EL817 optocoupler provides complete electrical isolation between the low-voltage microcontroller side and the high-voltage load side of the circuit. This protects your MCU from voltage spikes, noise, and back-EMF that can occur when switching inductive loads, greatly improving the reliability and longevity of your entire project. Q: What does the dual power supply design mean? A: The dual power supply design means the control circuit (MCU side) and the relay coil/load circuit are powered separately. This minimizes electrical interference between the two sides, ensuring stable and accurate relay switching even in electrically noisy environments. {"@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [{"@type": "Question", "name": "Is this optocoupler relay module compatible with Arduino and Raspberry Pi?", "acceptedAnswer": {"@type": "Answer", "text": "Yes! The DC 3V/3.3V relay module is fully compatible with Arduino, Raspberry Pi, ESP8266, ESP32, and any other microcontroller that outputs a 3V or 3.3V high-level signal on its I/O pins. Simply connect the signal pin from your MCU to the module's input and it will trigger reliably every time."}}, {"@type": "Question", "name": "What is the maximum load this relay module can switch?", "acceptedAnswer": {"@type": "Answer", "text": "This isolated relay module can handle loads up to 10A at 250VAC or 10A at 30VDC, making it suitable for controlling household lighting, small motors, solenoid valves, and other moderate-power devices safely from a low-voltage microcontroller signal."}}, {"@type": "Question", "name": "Why does this relay module use optical isolation (optocoupler)?", "acceptedAnswer": {"@type": "Answer", "text": "The EL817 optocoupler provides complete electrical isolation between the low-voltage microcontroller side and the high-voltage load side of the circuit. This protects your MCU from voltage spikes, noise, and back-EMF that can occur when switching inductive loads, greatly improving the reliability and longevity of your entire project."}}, {"@type": "Question", "name": "What does the dual power supply design mean?", "acceptedAnswer": {"@type": "Answer", "text": "The dual power supply design means the control circuit (MCU side) and the relay coil/load circuit are powered separately. This minimizes electrical interference between the two sides, ensuring stable and accurate relay switching even in electrically noisy environments."}}]}
