If you’re into DIY projects, you’re probably familiar with relays. These devices are essential for controlling the flow of electricity in various applications. And among the different types of relays available, the 4 prong relay is one of the most commonly used. In this article, we’ll discuss everything you need to know about 4 prong relay wiring diagrams, including how they work, their applications, and how to install them.
What is a 4 Prong Relay?
A 4 prong relay, also known as a 4 pin relay, is an electromechanical switch that uses an electromagnetic field to control the connection and disconnection of electrical circuits. It has four pins or terminals that are used to connect the relay to the power source and the load. The four pins are:
- Normally open (NO)
- Normally closed (NC)
- Common (COM)
- Coil input (COIL)
How Does a 4 Prong Relay Work?
A 4 prong relay works by using an electromagnetic field to switch between the NO and NC terminals. When the relay is activated, the NO terminal gets connected to the COM terminal, while the NC terminal gets disconnected. Conversely, when the relay is deactivated, the NC terminal gets connected to the COM terminal, while the NO terminal gets disconnected. This switching mechanism allows the relay to control the flow of electricity between two circuits.
Where are 4 Prong Relays Used?
4 prong relays are used in a wide variety of applications, including:
- Automotive electronics
- Home automation systems
- Industrial control systems
- Robotics
- Security systems
How to Wire a 4 Prong Relay
Wiring a 4 prong relay is relatively simple, but it’s important to follow the correct wiring diagram to avoid damaging the relay or the connected devices. Here’s a step-by-step guide on how to wire a 4 prong relay:
- Identify the NO, NC, COM, and COIL terminals of the relay.
- Connect one end of the power source (usually 12V DC) to the COM terminal, and the other end to either the NO or NC terminal, depending on your desired switching configuration.
- Connect the load (e.g. a light bulb, a motor, or a solenoid) to the other terminal (either the NC or NO) that you didn’t connect to the power source in step 2.
- Connect one end of a switch (e.g. a push button or a toggle switch) to the COIL terminal of the relay, and the other end to the ground or negative terminal of the power source.
- If your switch is normally open (i.e. it doesn’t close the circuit when not pressed), connect the COIL terminal to the positive terminal of the power source, and connect the switch between the COIL terminal and the ground.
Example Wiring Diagram:
| Terminal | Wire Color | Connection |
|---|---|---|
| NO | Red | Connected to power source (+) |
| NC | White | Connected to load |
| COM | Black | Connected to power source (-) |
| COIL | Green | Connected to switch and ground (-) |
FAQs
Q: What is the difference between a NO and NC terminal?
A: The NO terminal (normally open) is the terminal that gets connected to the COM terminal when the relay is activated, while the NC terminal (normally closed) is the terminal that gets disconnected from the COM terminal when the relay is activated.
Q: How can I tell if a 4 prong relay is working?
A: You can test a 4 prong relay by using a multimeter to check the continuity between the NO and COM terminals when the relay is activated, and between the NC and COM terminals when the relay is deactivated. If there’s no continuity, the relay may be faulty or wired improperly.
Q: Can I use a 4 prong relay to control AC power?
A: Yes, but you need to make sure that the relay is rated for the voltage and current of the AC circuit you’re controlling. You should also use proper insulation and follow safety precautions when working with AC power.
Q: Can I daisy chain multiple 4 prong relays?
A: Yes, but you need to make sure that each relay is wired properly and can handle the load of the connected devices. You should also avoid exceeding the maximum current and voltage ratings of the relays and the power source.
Q: Can I use a 4 prong relay without a switch?
A: Yes, you can use a 4 prong relay with a logic circuit or a microcontroller that provides the input signal for the COIL terminal. However, you need to make sure that the input signal is within the specified voltage and current range of the relay.
Now that you know everything about 4 prong relay wiring diagrams, you can confidently tackle your next DIY project with ease. Remember to follow safety precautions and use proper insulation when wiring relays and electrical circuits. Happy tinkering!
