8-Pin Timer Relay Pinout Diagram, Wiring & Connection Explained
Understanding how an 8-pin timer relay works is essential for anyone working with electrical control circuits or automation systems, such as motor control, industrial machinery control, and many others. In this article, we are going to learn everything that you need to know about the 8-pin timer relay, from its pinout diagram and terminal identification to wiring procedures and functions. This article helps you a lot to understand a step-by-step guide on how to connect an 8-pin timer relay with any electrical control circuit.
Pinout Diagram and Terminal Identification
The 8-pin timer relay consists of several key terminals that serve different purposes in controlling the timing function. Understanding each terminal will help you connect your relay correctly and ensure it functions as intended.
Below, I have described all the terminals,
Pin 2 and Pin 7
These are the coil terminals of the timer relay. Pin 2 (generally marked as "+" or" L"). It needs to connect to the positive supply voltage, while Pin 7 (generally marked as "-" or "N"). It needs to connect to the negative side of the power supply. When voltage is applied to these terminals, it activates the relay, causing it to start its timing function.
Pin 1 (Common), Pin 4 (NC - Normally Closed), and Pin 3 (NO - Normally Open)
Pin 1 serves as the common terminal, where you connect the input or signal for the load you are controlling. Pin 4 is the Normally Closed (NC) terminal, meaning that in the default state (before the timer has been triggered), it will be connected to Pin 1. When the relay is triggered, this connection is opened, and Pin 4 stops conducting. Pin 3 is the Normally Open (NO) terminal. In the relay’s default state, this terminal remains disconnected from Pin 1 (Common). When the relay is activated, Pin 3 closes the circuit, allowing current to flow through to the connected load or device.
Pin 8 (Common), Pin 5 (NC - Normally Closed), and Pin 6 (NO - Normally Open)
Pin 8 serves as the common terminal, where you connect the input or signal for the load you are controlling. Pin 5 is the Normally Closed (NC) terminal, meaning that in the default state (before the timer has been triggered), it will be connected to Pin 8. When the relay is triggered, this connection is opened, and Pin 5 stops conducting. Pin 6 is the Normally Open (NO) terminal. In the relay’s default state, this terminal remains disconnected from Pin 8 (Common). When the relay is activated, Pin 6 closes the circuit, allowing current to flow through to the connected load or device.
Wiring Diagram
The wiring diagram below shows how to connect an 8-pin relay. For a better understanding, we have used light bulbs as electrical loads.
Connection Procedure
Here is the connection procedure of an 8-pin timer relay. This connection procedure will work for both off-delay and on-delay relays, you just need to ensure that you use the correct type of relay or that your relay is set to the correct timer mode for your applications.
Step 1: Power the Relay Coil
- Connect Pin 2 to the positive terminal of your power supply (e.g., 230V AC or 24V DC, depending on your relay type).
- Connect Pin 7 to the negative or neutral terminal of your power supply.
Step 2: Connect the First Load (using Pin 1, 3, and 4)
This section controls one device or circuit. Pin 1 is the common terminal.
- If you want the device to be normally ON (i.e., powered before the timer starts), connect the load between Pin 4 (NC) and one side of the power supply. Once the timer activates, the connection will open and turn the device OFF.
- If you want the device to be normally OFF (i.e., powered only after the timer is triggered), connect the load between Pin 3 (NO) and one side of the power supply. Once the timer completes its delay, this circuit will close and power the device.
Step 3: Connect the Second Load (using Pin 8, 5, and 6)
This section allows control of a second device or circuit independently. Pin 8 is the second common terminal.
- To keep the second device normally ON, connect it between Pin 5 (NC) and power.
- To keep it normally OFF, connect it between Pin 6 (NO) and power.
Step 4: Adjust Time Delay (if applicable)
- Most timer relays have a dial or selector switch to set the delay time and operation mode (like ON-delay, OFF-delay, cyclic, etc.).
- Use a small screwdriver or your fingers to rotate the knob to the desired time (e.g., 5 seconds, 30 seconds, etc.).
- Make sure the mode is set according to your application (check the relay label or datasheet).
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