Relays are a type of electromechanical switch that can be used to control various electrical circuits. A 12V relay can be easily wired to a switched power source, and is commonly used in automotive and marine applications. In this article, we will discuss the wiring diagram for a 12V relay that is connected to a switched power source.
What is a 12V Relay?
A 12V relay is an electrical component that is used to switch a high current circuit with a low current circuit. It consists of a coil and a set of contacts that are mechanically linked. When voltage is applied to the coil, it creates a magnetic field that attracts the contacts, closing the circuit. A 12V relay is commonly used in automotive and marine applications to control various electrical circuits such as lights, horns, and fans.
How Does a 12V Relay Work?
A 12V relay works by using the electromagnetic effect to close the circuit. When voltage is applied to the coil, it creates a magnetic field that attracts the contacts, closing the circuit. The contacts are opened when the voltage is removed from the coil. The contacts can be normally open (NO) or normally closed (NC), depending on the type of relay.
Relays are important because they allow low current circuits to control high current circuits without the risk of damaging the low current circuit. They also allow for multiple circuits to be controlled by one switch, improving the efficiency of the electrical system.
Wiring a 12V Relay to Switched Power Source
The wiring for a 12V relay that is connected to a switched power source is relatively simple. The relay is wired in series with the load, and the switch is connected to the 12V power source. The power source is only connected to the coil of the relay, allowing the switch to control the circuit.
Materials Required
The materials required to wire a 12V relay to a switched power source are:
- 12V Relay
- Switch
- Connector
- Wire Strippers and Cutters
- Electrical Tape
- Wire
Step-by-Step Guide
Follow the steps below to wire a 12V relay to a switched power source:
- Identify the switched power source that you want to connect the relay to. This could be a fuse box, ignition switch, or other switched power source.
- Connect the 12V power source wire to one of the relay’s coil terminals.
- Connect the other coil terminal to the switch.
- Connect one of the load wires to the relay’s NO terminal.
- Connect the other load wire to the other side of the switch.
- Secure all connections with electrical tape or wire connectors.
Wiring Diagram
The wiring diagram for a 12V relay that is connected to a switched power source is shown below:
| Terminal | Wire Color | Description |
| 85 | Black | 12V Power Source |
| 86 | Red | Switch |
| 87 | Yellow | Load |
| 87a | N/A | NC Contact (Optional) |
| 30 | N/A | Common Contact |
FAQ
What is the difference between a NO and NC contact?
A NO (normally open) contact is open when the relay is not energized, and closes when the relay is energized. An NC (normally closed) contact is closed when the relay is not energized, and opens when the relay is energized.
Can a 12V relay be used with a higher voltage circuit?
No, a 12V relay should only be used with a 12V circuit. Using a 12V relay with a higher voltage circuit can result in damage to the relay and/or the electrical system.
Can a 12V relay be used to control multiple circuits?
Yes, a 12V relay can be used to control multiple circuits by wiring the loads in parallel with each other. However, the relay should be rated for the total current of all loads combined.
What is the maximum current that a 12V relay can handle?
The maximum current that a 12V relay can handle depends on the specific relay. It is important to check the relay’s datasheet to determine the maximum current rating.
What is the purpose of the connector?
The connector is used to connect the wires to the relay and switch. It provides a secure and reliable connection that is easy to remove if necessary.
