Relay card Unit U-Relay-Card-SP 5V 16A — single-pole relay board for low-voltage control

Unit U-Relay-Card-SP 5V 16A is a single-pole relay board designed for low-voltage control applications. The module features a 5 V coil for easy interfacing with microcontrollers, control panels and low-voltage drivers, while its 16 A switching capacity supports direct control of moderate electrical loads. The compact PCB layout and standard relay footprint make the card simple to mount and wire into automation projects, prototypes or retrofit installations where reliable mechanical switching is required.

Advantages

The relay card provides a compact physical size combined with a robust switching rating suitable for many general-purpose loads. A low-voltage 5 V drive removes the need for high-voltage coils or additional driver circuits when used with common logic-level controllers. The single-pole contact arrangement simplifies wiring for on/off control and reduces the complexity of integration into existing systems. The board’s construction prioritizes accessible terminal connections and predictable electrical behaviour under its rated conditions.

Suitable for

• Home and industrial automation switching
• Control panels and relay expansion modules
• Prototyping with microcontrollers (Arduino, Raspberry Pi with proper interfacing)
• Replacement of mechanical switches and manual relays

Key specifications

• Coil voltage: 5 V DC
• Maximum switching current: 16 A (resistive load)
• Contact configuration: single-pole (SP)
• Operating type: electromechanical relay on PCB
• Typical mounting: compact PCB footprint for panel or enclosure integration

How to use

Connect the 5 V control input to a suitable logic-level output or driver that can supply the relay coil current; ensure the control source can handle inrush and steady coil current. Wire the switched load through the relay’s contact terminals, observing the rated 16 A limit and using appropriate gauge conductors and fuse or circuit protection. Provide a common ground if required by the control circuit and observe polarity for the coil connections. When integrating with microcontrollers, include a flyback diode or driver transistor as needed if the relay board does not provide internal suppression.

Recommendations

Use the relay card within its specified coil voltage and switching current limits; for inductive loads such as motors or solenoids, add appropriate suppression (diodes, RC snubbers, or surge protectors) and consider derating the switching current. Install adequate fusing and maintain safe creepage and clearance distances in enclosure designs. Verify thermal conditions during extended switching cycles and ensure terminal connections are tightened to the manufacturer’s torque recommendations.