What is the Difference Between Relay and Switch?

Control and conditioning of electrical and electronic systems are surrounded by the need to understand the elements that govern circuits. Two of the instruments that are frequently applied for these purposes are relays and switches. Although both are used to regulate the flow of electricity, they work in different principles and are mostly used in different settings. Relay and switch are terms that are often used interchangeably, making this blog essential to read to identify the difference between the terms, their uses, and why it is important to know the difference between the two.

What is Relay?

A relay is categorised as an electromechanical or solid-state for controlling a high-power circuit by a low-power signal. More so, it operates like an electrical switch that can either make or break a circuit depending on the incoming electrical signal. Relay is employed in many circuits where it is required to switch a high current with a small current, found in the automobile, industries, domestic circuits, etc.

How do Relays Work?

The operation of a relay is basically a simple process where a coil is energised, and a magnetic field is created and used by an armature and one or more sets of contacts. On passing an electric current through the coil, a magnetic field is set up, and this attracts the armature to the contact. Depending on the relay type or, in other words, whether that relay is normally open or normally closed, this movement either makes a circuit whole or interrupts it.

Uses of Relay:

Relays are extensively employed in many areas due to their effectiveness in switching high-power appliances by employing a low-energy signal. Common uses of relay include:

• Automotive Systems: Relays operate different functions, including headlights, horns and fuel pumps, to name but a few.

• Industrial Control Systems: They are essential in automation systems where they handle motors and heating elements, among other high-power devices or appliances.

• Home Appliances: They are applied in washing machines, air conditioners and other household electrical appliances to control power supplied to various sub assemblies.

What is a Switch?

A switch is a very basic object that works by directly controlling the flow of electricity on a circuit. It functions directly or with the use of an electromagnet opening or closing a circuit to let current through or stop the flow. Switches are part of a man’s everyday life starting from the switch on the wall to the power button in a computer.

How Switches Work?

A switch basically works on opening or closing two terminals in a circuit. This position enables the current to be free to pass through the circuit if the switch is located in the “on” position. However, when it is in the “off position”, the circuit is broken and cuts off the flow of current.

Uses of Switches

Switches are used in almost all electrical appliances and circuits in the current market. Some common uses of switch include:

• Lighting: Bulbs are employed to illuminate homes, offices, and industrial applications and switches are employed to power ‘ON’ or ‘OFF’ the bulb.

• Electronics: Power switches are used in operating devices like computers, television sets, radios, etc.

• Machinery: In industrial machines, switches are employed for start/stop or the management of several functions.

Relay vs Switch: Main Distinctions

A relay and a switch both act to regulate circuits, though they function differently and are applied differently. Here in the following section, it will be rather appropriate to describe the primary distinctions between relay and switch.

Operation

• Relay: A relay is operated through an electrical signal originating from outside; hence, it is an automatic device. Electromagnetic is the switch type based on electromagnetism, while solid-state is a switch that relies on solid-state technology to switch the circuit.
• Switch: A switch is usually of the form where movement is needed to effect a change from opening or closing the circuit. There are also switches that turn ON or OFF, with pre-set conditions such as temperature or light, but these are direct control switches.

Functionality 

• Relay: Relays are employed to switch high-power circuits with the help of low-power signals. They are very important in applications where it is required to have a separation between the control circuit and the controlled circuit, as in automotive and industrial uses.

• Switch: Switches are lever or button-operated devices employed to open and close circuits with the help of the human hand. It is a basic technology that does not need an elaborate source of energy to run the machines that incorporate such technology.

Complexity

• Relay: Switches are simple devices in contrast to the relays; relays have coils, armatures, and contacts as main parts. This complexity enables them to do more complex operations such as switching of individual circuits or provision of isolation.

• Switch: Switches are also relatively uncomplicated devices which contain only a few elements. Thus they are easier to use and in installation. As relays, their simplicity makes them suitable for providing simple on/off control solutions.

Applications

• Relay: The uses of relays are more appropriate in the events of automation, remote operation or high power switching. These are typically incorporated in industrial control systems, automotive systems, and advanced domestic gadgets.

• Switch: The uses of switches are even more extensive, with instances locating themselves ubiquitously in the day to day life. Switches are essential parts of any normal electrical gadget right from switching on a light bulb to operating a kitchen gadget.

Also Read: Contactor vs Relay: Understand Key Differences and Applications

Summing Up

Understanding the difference between relay and switch is essential for selecting the right component for your electrical or electronic project. Relays and switches, while performing similar functions, differ significantly in their operation, complexity, and application. A relay is best for controlling high-power circuits with a low-power signal and offers greater flexibility and safety in complex systems. On the other hand, a switch is ideal for simple, direct control in everyday applications. Buy the best relays and switches online easily from the eShop of Lauritz Knudsen Electrical and Automation.