Understanding the Five Pin Relay Wiring Diagram

The five pin relay wiring diagram is a fundamental concept for anyone working with automotive electrical systems, simple control circuits, or even basic home automation projects. Understanding this diagram allows for the safe and efficient control of higher-power devices using lower-power signals. This article will break down the intricacies of a five pin relay wiring diagram, making it accessible to a wide audience.

The Essentials of a Five Pin Relay Wiring Diagram

At its core, a five pin relay wiring diagram illustrates how to connect a relay with five terminals to a circuit. Relays are essentially electrically operated switches. They use a small electrical current to control a larger electrical current. This is incredibly useful because it allows a low-power component, like a switch in your car's dashboard or a microcontroller, to safely activate a high-power device, such as headlights, a fuel pump, or a fan, without the low-power component having to handle the high current directly. The five pins on a typical automotive relay are standardized for ease of use and interchangeability.

A standard five pin relay has the following pins, each with a specific function:

• 85: Coil Ground - This pin is connected to the negative side of the control circuit.
• 86: Coil Power - This pin is connected to the positive side of the control circuit, often through a switch or a control module. When power is applied to both pin 85 and 86, the relay coil is energized.
• 30: Common Terminal - This is the main power input terminal that can be switched to either the normally open or normally closed contact.
• 87: Normally Open (NO) Terminal - When the relay coil is energized, this terminal is connected to the common terminal (pin 30).
• 87a: Normally Closed (NC) Terminal - When the relay coil is energized, this terminal is disconnected from the common terminal (pin 30). When the coil is de-energized, this terminal is connected to the common terminal.

The beauty of the five pin relay lies in its versatility. You can configure it to either break a circuit when activated (using the normally closed contact) or make a circuit when activated (using the normally open contact). The importance of correctly understanding and implementing a five pin relay wiring diagram cannot be overstated, as incorrect wiring can lead to device damage, electrical fires, or safety hazards.

Let's consider a simple example. Imagine you want to control a high-current accessory with a low-current switch. You would connect the switch and a power source to pins 85 and 86. Then, you would connect the positive power for the accessory to pin 30 and the accessory itself to pin 87. When you flip the switch, power energizes the relay coil, the internal switch closes, and power flows from pin 30 to pin 87, activating your accessory. This is a basic demonstration of how the "normally open" function is utilized. You can also use the "normally closed" contact (pin 87a) to interrupt power to a device when the relay is activated, for example, to disable a system under certain conditions.

Here's a table summarizing the states:

To truly grasp the practical application of a five pin relay wiring diagram, it is highly recommended to refer to the detailed illustrations and examples found in our comprehensive guide.