Relays are essential components of most electrical systems. Without relays, many systems would not function as they should. However, wiring relays can be a daunting task, especially if you are new to electrics. In this article, we will explore 12 relay wiring diagrams in detail to help you understand how they work and how to wire them correctly.
What are Relays?
A relay is an electromagnetic switch that is activated by an electrical signal. They are used to control high-current electrical circuits with low-current signals. Relays have a coil that produces a magnetic field when electricity passes through it. This magnetic field then closes or opens the switch contacts, which allows or stops the flow of current in the circuit.
Relays are used in a variety of applications, including automotive, industrial, and aerospace. They are essential components of many systems, such as power windows, air conditioning, and lighting systems.
12 Relay Wiring Diagrams
There are many different types of relays, and each has a unique wiring diagram. In this section, we will look at 12 common relay wiring diagrams:
- Single Pole Single Throw (SPST)
- Single Pole Double Throw (SPDT)
- Double Pole Single Throw (DPST)
- Double Pole Double Throw (DPDT)
- Normally Open (NO)
- Normally Closed (NC)
- Time Delay
- Latching
- Reed
- Solid State
- Automotive
- Industrial
1. Single Pole Single Throw (SPST)
The SPST relay is the simplest type of relay. It has a single set of contacts that are normally open (NO) when the coil is not energized. When the coil is energized, the contacts close (NC). This means that when the relay is powered, it will complete the circuit, and when it is not powered, it will break the circuit.
In the wiring diagram, the coil is connected to a power source, and the switch is connected to the load. When the switch is closed, the coil is energized, and the contacts close, allowing current to flow through the load.
2. Single Pole Double Throw (SPDT)
The SPDT relay has a single set of contacts that can switch between two positions. It has one normally open (NO) contact and one normally closed (NC) contact. When the coil is energized, the NO contact closes, and the NC contact opens.
In the wiring diagram, the coil is connected to a power source, and the switch is connected to the load. When the switch is closed, the coil is energized, and the NO contact closes, allowing current to flow through one circuit. When the switch is opened, the NC contact closes, allowing current to flow through a second circuit.
3. Double Pole Single Throw (DPST)
The DPST relay has two sets of contacts that are both normally open (NO) when the coil is not energized. When the coil is energized, both sets of contacts close.
In the wiring diagram, the coil is connected to a power source, and the switch is connected to the load. When the switch is closed, the coil is energized, and both sets of contacts close, allowing current to flow through the load.
4. Double Pole Double Throw (DPDT)
The DPDT relay has two sets of contacts that can switch between two positions. It has two normally open (NO) contacts and two normally closed (NC) contacts. When the coil is energized, both NO contacts close, and both NC contacts open.
In the wiring diagram, the coil is connected to a power source, and the switch is connected to the load. When the switch is closed, the coil is energized, and both NO contacts close, allowing current to flow through one circuit. When the switch is opened, both NC contacts close, allowing current to flow through a second circuit.
5. Normally Open (NO)
The NO relay is a type of SPST relay. It has a single set of contacts that are normally open (NO) when the coil is not energized. When the coil is energized, the contacts close.
In the wiring diagram, the coil is connected to a power source, and the switch is connected to the load. When the switch is closed, the coil is energized, and the contacts close, allowing current to flow through the load.
6. Normally Closed (NC)
The NC relay is a type of SPST relay. It has a single set of contacts that are normally closed (NC) when the coil is not energized. When the coil is energized, the contacts open.
In the wiring diagram, the coil is connected to a power source, and the switch is connected to the load. When the switch is closed, the coil is energized, and the contacts open, allowing current to flow through the load.
7. Time Delay
The time delay relay is a type of SPDT relay. It has a single set of contacts that can switch between two positions. It has one normally open (NO) contact and one normally closed (NC) contact. When the coil is energized, the contacts switch positions after a set amount of time has passed.
In the wiring diagram, the coil is connected to a power source, and the switch is connected to the load. When the switch is closed, the coil is energized, and the NO contact closes, allowing current to flow through the load. After a set amount of time has passed, the NC contact opens, breaking the circuit.
8. Latching
The latching relay is a type of SPDT relay. It has a single set of contacts that can switch between two positions. It requires two pulses to switch between the positions. When the first pulse is applied to the coil, the contacts switch positions. When the second pulse is applied, they switch back.
In the wiring diagram, the coil is connected to a power source, and the switch is connected to the load. When the first pulse is applied, the contacts switch positions, allowing current to flow through the load. When the second pulse is applied, the contacts switch back, breaking the circuit.
9. Reed
The reed relay is a type of SPST relay. It has a single set of contacts that are normally open (NO) when the coil is not energized. When the coil is energized, a magnetic field is produced that closes the contacts.
In the wiring diagram, the coil is connected to a power source, and the switch is connected to the load. When the switch is closed, the coil is energized, and the contacts close, allowing current to flow through the load.
10. Solid State
The solid-state relay is a type of relay that does not have any moving parts. It uses semiconductor devices to switch the load on and off. It is more reliable and has a longer lifespan than mechanical relays.
In the wiring diagram, the control signal is connected to the input of the solid-state relay, and the load is connected to the output. When the control signal is applied, the output turns on, allowing current to flow through the load.
11. Automotive
The automotive relay is a type of relay that is commonly used in automobiles. It is designed to withstand the harsh operating conditions of a vehicle. It is typically rated for 12 volts and can handle high currents.
In the wiring diagram, the coil is connected to a power source, and the switch is connected to the load. When the switch is closed, the coil is energized, and the contacts close, allowing current to flow through the load.
12. Industrial
The industrial relay is a type of relay that is used in industrial applications. It is designed to handle high currents and voltages. It is typically rated for 120 or 240 volts and can handle currents of up to 30 amps.
In the wiring diagram, the coil is connected to a power source, and the switch is connected to the load. When the switch is closed, the coil is energized, and the contacts close, allowing current to flow through the load.
Frequently Asked Questions (FAQ)
What is a relay used for?
A relay is used to control high-current electrical circuits with low-current signals. They are used in a variety of applications, including automotive, industrial, and aerospace.
How do you wire a relay?
Wiring a relay involves connecting the coil to a power source and connecting the contacts to the load.
What are the different types of relays?
There are many different types of relays, including SPST, SPDT, DPST, DPDT, NO, NC, time delay, latching, reed, solid state, automotive, and industrial.
What is a time delay relay?
A time delay relay is a type of relay that switches positions after a set amount of time has passed.
What is a latching relay?
A latching relay is a type of relay that requires two pulses to switch between positions.
What is a reed relay?
A reed relay is a type of relay that uses a magnetic field to close the contacts.
What is a solid-state relay?
A solid-state relay is a type of relay that uses semiconductor devices to switch the load on and off.
What is an automotive relay?
An automotive relay is a type of relay that is used in automobiles. It is designed to withstand the harsh operating conditions of a vehicle.
What is an industrial relay?
An industrial relay is a type of relay that is used in industrial applications. It is designed to handle high currents and voltages.
Conclusion
Wiring relays can be a challenging but necessary task for any electrical system. Understanding the different types of relays and their wiring diagrams can help you wire your system correctly and avoid potential problems. We hope this article has provided you with valuable information about 12 relay wiring diagrams.
