The 1-Way 3.3V BESTEP Electromagnetic Relay Module is a compact, high-reliability switching board designed for microcontroller and PLC-based control systems. It features optocoupler isolation between the control signal and the relay coil, ensuring that your sensitive 3.3V logic circuits are protected from voltage spikes and electrical noise generated by the relay and connected loads. The module uses a low-level trigger design, meaning the relay activates when the input signal is pulled LOW (0V).
At the heart of the module is a high-quality electromagnetic relay capable of switching AC or DC loads up to 10A at 250V AC or 10A at 30V DC. This makes it suitable for controlling lamps, motors, solenoids, heaters, and other household or industrial devices directly from a 3.3V logic signal. The relay provides Normally Open (NO) , Normally Closed (NC) , and Common (COM) contacts for flexible wiring configurations.
The optocoupler isolation is a key safety feature. It creates a galvanic barrier between the control side (your microcontroller or PLC) and the load side (the relay and connected equipment). This protects your 3.3V logic circuits from back-EMF, voltage transients, and ground loops that can occur when switching inductive loads such as motors and solenoids.
The module is designed for 3.3V logic compatibility, making it ideal for modern microcontrollers like ESP32, ESP8266, STM32, and Raspberry Pi, as well as 3.3V PLC systems. The low-level trigger design means the relay is activated when the input pin is pulled to ground, which is convenient for many control applications.
The board features screw terminals for secure connection of the load wiring, and pin headers for easy connection to your microcontroller. LED indicators provide visual feedback: a power LED and a relay status LED that lights up when the relay is activated. The compact PCB design with mounting holes makes it easy to integrate into control panels, equipment enclosures, and custom projects.
The module is widely used in PLC control systems, home automation, industrial automation, IoT projects, smart switches, and any application where a low-voltage logic signal needs to control a higher-power load. It is also popular in educational projects for teaching relay control and optocoupler isolation principles.
Important Note: The relay is rated for 10A at 250V AC or 30V DC. For inductive loads such as motors, it is recommended to keep the load current below 60–70% of the rated value for reliable operation. Always ensure proper isolation and safety precautions when working with mains voltage.
Whether you are building a smart home controller, automating an industrial process, or adding relay control to a 3.3V microcontroller project, the 1-Way 3.3V BESTEP Electromagnetic Relay Module provides a reliable, isolated solution. It is suitable for individual makers, students, and businesses purchasing in bulk for product development or industrial applications.
Features
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1-way relay output — Single-channel switching for AC or DC loads
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Optocoupler isolation — Protects control circuits from load-side noise and voltage spikes
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3.3V logic compatible — Ideal for ESP32, ESP8266, STM32, Raspberry Pi, and 3.3V PLCs
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Low level trigger — Relay activates when input is pulled LOW
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High-current relay — 10A at 250V AC / 30V DC switching capacity
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LED indicators — Power LED and relay status LED for visual feedback
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Screw terminals — Secure connection for load wiring
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Pin headers — Easy connection to microcontroller
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Compact PCB design — With mounting holes for easy installation
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Wide application range — PLC control, home automation, industrial automation, IoT
Technical Specifications
| # | Parameter | Specification |
|---|---|---|
| 1 | Channels | 1 (single-way) |
| 2 | Relay Rating | 10A at 250V AC / 10A at 30V DC |
| 3 | Control Voltage | 3.3V DC |
| 4 | Trigger Type | Low level trigger |
| 5 | Isolation | Optocoupler isolation |
| 6 | Contacts | NO / NC / COM |
| 7 | Indication | Power LED + relay status LED |
| 8 | Terminal Type | Screw terminals + pin headers |
