Relays are essential components in the world of electrical engineering. They can help in the automation of electric devices, protect them from overload, and even switch between different circuits. One of the most commonly used relays is the 4 pin relay. It comes with a switch that makes it easy to control the relay’s connection with the circuit. This article will guide you through the usage and wiring of a 4 pin relay with a switch.
What is a 4 Pin Relay?
A 4 pin relay is a type of electromechanical switch that operates using an electromagnetic field. It has four terminals, which include two for the coil and two for the switch. The coil is responsible for creating the magnetic field that closes the switch, allowing current to flow through it. These relays are commonly used in automotive electrical systems, as well as industrial machinery.
The 4 pin relay’s construction features a spring-loaded armature that is pulled towards the electromagnet when the coil is energized. This armature closes the switch contacts, which then allows current to flow through to the output terminals. This process is reversible, and the switch contacts will open when the coil is de-energized.
How to Wire a 4 Pin Relay with a Switch?
Wiring a 4 pin relay with a switch involves connecting the switch to the relay’s coil terminals or pins. The switch should be connected to the coil terminals in a way that when the switch is open, the coil is de-energized, and the switch contacts are open, and when the switch is closed, the coil is energized, and the switch contacts are closed.
Below is a step by step guide on how to wire a 4 pin relay with a switch.
Step 1: Gather the Required Components
The following are the components required for wiring a 4 pin relay with a switch:
| Component | Quantity |
|---|---|
| 4 pin relay | 1 |
| Switch | 1 |
| Wires | As needed |
| Battery | 1 (optional) |
Step 2: Identify the Relay Pins
The 4 pin relay has four terminals or pins, which include:
- Pin 30: Common (C)
- Pin 85: Coil negative (-)
- Pin 86: Coil positive (+)
- Pin 87: Normally open (NO)
You can use a multimeter to identify the pins if they are not labeled on the relay.
Step 3: Identify the Switch Terminals
The switch has two terminals: Normally Open (NO) and Normally Closed (NC). The NO terminal should be connected to the relay’s coil terminals.
Step 4: Connect the Components
The following steps show how to wire the components:
- Connect one wire from the positive terminal of the battery to the switch’s NO terminal.
- Connect the other wire from the switch’s NO terminal to the relay’s positive (+) coil (pin 86).
- Connect a wire from the relay’s negative (-) coil (pin 85) to the negative terminal of the battery.
- Connect a wire from the relay’s normally open (NO) (pin 87) to the positive end of the device that you want to energize.
- Connect a wire from the negative end of the device to the negative terminal of the battery.
Step 5: Test the Circuit
Once you have completed the wiring, you can now test the circuit by turning the switch on and off. When the switch is in the off position, the device should not receive power, and when the switch is on, the device should receive power.
FAQs
What is the difference between a 4 pin relay and a 5 pin relay?
The main difference between a 4 pin relay and a 5 pin relay is that the latter has an additional terminal for the normally closed (NC) switch. This switch allows an alternate circuit to be used when the relay is not energized or powered.
What is the difference between a normally open (NO) and normally closed (NC) switch?
In a normally open (NO) switch, the contacts are open when the switch is not activated or energized. When the switch is activated, the contacts close, thereby completing the circuit. In a normally closed (NC) switch, the contacts are closed when the switch is not activated. When the switch is activated or energized, the contacts open, which breaks the circuit.
Can a 4 pin relay be used to control multiple devices?
Yes, a 4 pin relay can be used to control multiple devices by connecting each device to a separate relay. This approach is ideal when you want to control each device independently.
Can a 4 pin relay be used in both AC and DC circuits?
Yes, a 4 pin relay can be used in both AC and DC circuits. However, you should ensure that the relay’s voltage rating matches that of the circuit you want to control.
Can a 4 pin relay be used to switch a high voltage load?
Yes, a 4 pin relay can switch a high voltage load, but you should ensure that the relay’s current rating matches that of the load.
In conclusion, a 4 pin relay with a switch is a versatile and essential component in electrical engineering. By following the steps and guidelines provided in this article, you can successfully wire a 4 pin relay with a switch and control different electrical devices with ease.
