12v Relay Wiring Diagram 5 Pin

Hello and welcome! In this article, we will discuss the 12v relay wiring diagram 5 pin in detail. A relay is an essential component in electrical circuits that helps control high-current devices with the help of low-current signals. Understanding the wiring diagram is crucial for proper installation and functioning of the relay. So, let’s dive in and explore the various aspects of the 12v relay wiring diagram 5 pin.

1. Purpose of a 12v Relay

A 12v relay is designed to control the flow of electrical current to various components or devices in a circuit. It acts as a switch that can be controlled by a low-current signal, such as from a switch or a microcontroller. The 5 pins on the relay are used for various connections, including power supply, control signal, and output connections.

2. Pin Configuration

The 12v relay wiring diagram 5 pin consists of five pins with specific functions. The pins are labeled as follows:1. Pin 30: Common contact or power supply input2. Pin 87: Normally open (NO) contact or output3. Pin 87a: Normally closed (NC) contact (not used in all relays)4. Pin 86: Control signal input (usually connected to the switch or microcontroller)5. Pin 85: Ground or negative supply

3. Wiring Connections

Proper wiring connections are crucial for the relay to function correctly. The power supply is connected to pin 30, which is the common contact. The device or component that needs to be controlled is connected to pin 87, the normally open contact. Pin 86 receives the control signal, and pin 85 is connected to the ground or negative supply.

4. Wiring Diagram

A wiring diagram visually represents the connections and layout of the 12v relay wiring. It helps in understanding the wiring configuration and ensures accurate installation. Here is a basic wiring diagram for a 12v relay with 5 pins:

Pin Function Connection
30 Common contact Power supply
87 Normally open contact Device/component
87a Normally closed contact (if available) Not used
86 Control signal input Switch/microcontroller
85 Ground/negative supply Ground

5. Advantages of Using a 12v Relay

There are several advantages of using a 12v relay in electrical circuits:

  • Allows control of high-current devices with low-current signals.
  • Provides isolation between the control signal and the high-current load.
  • Enhances circuit reliability and protection by preventing damage to sensitive control components.
  • Enables automation and remote control of devices.
  • Offers versatility in circuit design and customization.

6. Disadvantages of Using a 12v Relay

While there are many advantages, it’s important to consider the disadvantages as well:

  • Relays consume power and may introduce power losses.
  • Relays have a limited switching speed compared to solid-state devices.
  • Mechanical relays may produce audible noise during operation.
  • Relays have a finite lifespan and may require periodic maintenance or replacement.

7. Alternative Wiring Diagrams

There are alternative wiring configurations for a 12v relay depending on the specific application requirements. Some relays may have additional pins or different pin functions. It’s important to refer to the datasheet or manufacturer’s instructions for the specific relay being used. Always ensure proper understanding of the wiring diagram to avoid any issues or malfunctions.

8. Frequently Asked Questions (FAQ)

Q: Can I use a 12v relay for higher voltage applications?A: Yes, a 12v relay can often be used for higher voltage applications by selecting a relay with an appropriate voltage rating for the specific requirements. However, it’s important to consider factors such as current rating and contact durability as well.

Q: How do I test a 12v relay?A: To test a 12v relay, you can use a multimeter to check for continuity between the appropriate pins when the control signal is applied. You can also listen for audible clicks, indicating the operation of the relay.

Q: Can I connect multiple devices to a single relay?A: Yes, you can connect multiple devices to a single relay by using appropriate wiring connections and ensuring that the relay can handle the combined current requirements of the devices.

Q: Are there different types of relays available?A: Yes, there are various types of relays available, such as electromagnetic relays, solid-state relays, thermal relays, and more. Each type has its own advantages and applications.


In conclusion, understanding the 12v relay wiring diagram 5 pin is essential for proper installation and functionality. The wiring connections and pin configuration play a crucial role in controlling high-current devices with low-current signals. By following the correct wiring diagram and considering the advantages and disadvantages, you can effectively incorporate a 12v relay into your electrical circuits. Remember to refer to the manufacturer’s instructions and datasheet for the specific relay being used to ensure accurate wiring connections and safe operation.