The 5V 5-Pin Relay is an electromechanical switching component in modern electronic and automation systems.This article will discuss the overview, pin configuration, specifications, features, applications, proper usage, and safety considerations of the 5V 5-Pin Relay.

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5V 5-Pin Relay Overview

A 5V 5-Pin Relay (SRD series) is an electromechanical switch designed to let a low-voltage 5V control signal safely operate higher-voltage or higher-current loads.It is widely used in control and automation circuits where electrical isolation between the control side and load side is required.

This relay typically features five pins: two coil pins for the 5V DC input, and three contact pins - COM (Common), NO (Normally Open), and NC (Normally Closed).The contact structure is SPDT, allowing flexible switching logic depending on whether the load should turn on or off when the relay is energized.

When 5V is applied to the coil, an internal electromagnet moves the contact from NC to NO, enabling reliable switching of loads such as lamps, motors, pumps, or AC mains circuits.

5V 5-Pin Relay Pinout Details

Alternatives & Equivalent Models

• SRD-03VDC-SL-C (3 V coil relay)

• SRD-12VDC-SL-C (12 V coil relay)

• 5 V 1-Channel Relay Module (based on SRD relay)

• 5 V 4-Channel Relay Module (based on SRD relays)

5V 5-Pin Relay Specifications

5V 5-Pin Relay Features

• High switching capacity up to 10 A, despite its compact size, making it suitable for high-density PCB layouts.

• 5V DC coil operation, ideal for direct interfacing with microcontrollers and low-voltage control circuits.

• SPDT (1 Form C) contact configuration, providing both Normally Open (NO) and Normally Closed (NC) switching options.

• Certified for safety and reliability, with UL, cUL, and TÜV recognition for global compliance.

• Durable plastic housing, designed to withstand high operating temperatures and offer improved chemical resistance.

• Available in sealed and flux-proof versions, protecting internal components from dust, moisture, and solder flux.

• Low power consumption coil, reducing heat generation and improving energy efficiency.

• Simple and robust magnetic circuit design, optimized for stable operation and low-cost mass production.

• Fast operating and release times, ensuring responsive switching performance.

• Electrical isolation between coil and contacts, enhancing safety when controlling high-voltage or high-current loads.

• Long mechanical and electrical life, suitable for frequent switching applications in automation and control systems.

5V 5-Pin Relay Applications

• Domestic appliances

• Office machines

• Audio equipment

• Video equipment

• Television receivers

• Monitor displays

• Remote control systems

• Home automation systems

• Smart switches and IoT devices

• Industrial control panels

• Automation and PLC interfaces

• Motor control circuits

• Pump and fan control

• Power supply switching

• Battery management systems

• Automotive electronics

• Security and alarm systems

• Test and measurement equipment

• Lighting control systems

Using a 5V 5-Pin Relay in Electronic Circuits

Before using a 5V relay, it is important to understand two key parameters.The first is the trigger or coil voltage.A 5V relay requires a 5V DC supply to energize the coil and switch the internal contact from Common-NC to Common-NO.Selecting the correct coil voltage ensures stable operation and prevents unreliable switching.

The second parameter is the load voltage and current rating.These ratings define the maximum electrical limits the relay contacts can handle.Typical 5V relays support loads up to 30V DC at 10A, depending on the model.The connected load must remain within these limits to avoid contact damage, overheating, or premature failure.

A basic relay circuit uses a 5V DC supply connected to one side of the coil, while the other side is controlled by a switch, transistor, or microcontroller output.A flyback diode is connected across the coil in reverse bias to suppress voltage spikes generated when the relay turns off.This protects the control circuitry and improves long-term reliability.

On the load side, the supply voltage connects to the Common terminal, while the load is wired to either the Normally Open or Normally Closed contact.The NO contact keeps the load off until the relay is energized, while the NC contact keeps the load on by default.This simple configuration makes the 5V relay a flexible and reliable solution for many electronic switching applications.

5V 5-Pin Relay Safe Operation

To ensure safe operation of a 5V 5-pin relay, the coil must be driven with the correct voltage and sufficient current.Although the relay coil operates at 5 V DC, most microcontroller pins cannot supply the required current directly, so a transistor or relay driver circuit should be used.A flyback diode across the coil is strongly recommended to suppress voltage spikes when the relay is switched off, protecting sensitive control electronics.

The load connected to the relay contacts must always remain within the specified voltage and current ratings.Exceeding these limits can cause contact arcing, overheating, or premature failure.For AC mains applications, proper insulation distances, secure wiring, and certified enclosures are essential to reduce the risk of electric shock or fire.

Adequate PCB spacing between coil and contact traces should be maintained to preserve electrical isolation.In environments with moisture, dust, or chemical exposure, sealed relay versions are preferred.Regular inspection and correct mounting orientation further improve reliability and long-term safe operation.

5V 5-Pin Relay Mechanical Dimensions

Conclusion

The 5V 5-Pin Relay offers a practical balance of compact size, strong switching capability, and electrical isolation, making it suitable for a wide range of electronic and industrial applications.By understanding its pinout, operating principles, specifications, and safety requirements, users can integrate the relay confidently into control and automation circuits.When applied correctly, the 5V 5-Pin Relay remains a reliable and versatile component for switching tasks in both simple and advanced electronic systems.