Relays are an essential component in any electrical circuit that requires switching. They allow for the control of high current loads while keeping the control circuitry isolated. The 4-pin mini relay is a common type of relay used in automotive and industrial applications.
What is a 4 Pin Mini Relay?
A 4-pin mini relay is a type of electro-mechanical switch that consists of four pins or terminals. The pins are typically arranged in a square or rectangular shape, with two pins on each side. These relays are usually small in size and can handle moderate to high current loads.
Each pin on the mini relay has a specific function. The pins are numbered or labeled for easy identification. Pin 30 is the common, or C, pin. Pin 87 is the normally open, or NO, pin. Pin 85 is the relay’s coil positive, or +, pin, and pin 86 is the coil negative, or -, pin.
Wiring a 4 Pin Mini Relay
Wiring a 4-pin mini relay is relatively easy. The relay can be wired in either a Normally Open (NO) or Normally Closed (NC) configuration, depending on the application’s needs.
In a NO configuration, the load is connected to the NO pin, and the C pin is connected to a power source. The coil is connected to a switch or other control signal that activates the relay, closing the contact and allowing current to flow to the load. In an NC configuration, the load is connected to the NC pin, and the C pin is connected to a ground. When the coil is energized, the contact opens, interrupting the circuit, and stopping the flow of current to the load.
It is essential to follow the wiring diagram for the specific relay being used. It is also recommended to use a fuse or circuit breaker in the power source to protect the circuit from overloading or short-circuiting.
Mini Relay Pinout Diagram
The following table shows the pinout diagram for a typical 4-pin mini relay:
| Pin | Function |
|---|---|
| 30 | Common (C) |
| 87 | Normally Open (NO) |
| 85 | Coil Positive (+) |
| 86 | Coil Negative (-) |
FAQ
What is the difference between a NO and NC configuration?
A NO (Normally Open) configuration means that the contact is open when the relay is not energized, and the circuit is closed when the relay is energized. An NC (Normally Closed) configuration means that the contact is closed when the relay is not energized, and the circuit is open when the relay is energized.
What is the maximum current rating of a 4-pin mini relay?
The maximum current rating of a 4-pin mini relay varies depending on the specific model and manufacturer. It can range from a few amperes to several hundred amperes. It is essential to choose a relay with a current rating that matches the load requirements.
Can a 4-pin mini relay be used in both AC and DC circuits?
Yes, a 4-pin mini relay can be used in both AC and DC circuits. However, it is important to choose a relay that is rated for the specific application, as the coil may require different voltage levels and polarities for AC and DC circuits.
What are some common applications for 4-pin mini relays?
4-pin mini relays are commonly used in automotive applications, such as power windows, central locking, and headlights. They are also used in industrial applications, such as motor control, HVAC systems, and alarm and security systems.
Can a 4-pin mini relay be used to switch multiple loads?
Yes, a 4-pin mini relay can be used to switch multiple loads. However, it is important to ensure that the relay is rated for the total current and voltage requirements of all the loads.
Conclusion
A 4-pin mini relay is a versatile and commonly used component in various electrical circuits. Wiring a 4-pin mini relay requires following the wiring diagram for the specific relay being used and choosing the appropriate configuration and current rating for the application.
