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Advantages and Disadvantages of Relays

Relays serve as interface components. They can perform a variety of tasks. Relays can have advantages as well as disadvantages. Let’s look at them individually.

If they are switching, separating, amplifying or multiplying relays, they are used for different purposes within industrial controls. They are characterized by specific features and are available in a variety of types available in the market. Relays provide many benefits to the system and its users. A few of them are:

Simple and efficient operation

The working principle that a relay operates on is simple. The current that flows throughout the circuit of the relay generates an electric field that draws an object and alters the contact of the switch. This allows the control of the device remotely. A relay is activated using the use of a small current. However it is able to switch big circuits using a tiny amount of energy.

Circuit multiplication

A relay switch is able to switch multiple contacts at the same time. The same voltage can be used to carry out more than four switching functions. Each output contact on relays is able to switch circuits for load switching using different current and voltage levels.

Galvanic isolation

Relays are well-suited to provide safe galvanic isolation. Relays isolate the control circuit from load circuit. Even in the event of failures flash-overs between the contacts and coils are not common. Relays aren’t just an instrument for control, but also one of the safety devices.

Conversion of voltage

Relays can be used to switch low voltage signals to control larger loads. For instance the 24 V DC 10 mA signal could use to turn off to a 300 V AC 16 A load. More powerful loads are able to be managed using only a tiny amount of energy.

Accessory options

The whole relay body is comprised of an interface relay that plugs into a socket, holder, or functional module. Each component has its own function and can help improve the efficiency and efficiency of the relay.

For instance

A well-designed contact protection circuit could increase the lifespan of contacts by 5-10 times over inductive loads that aren’t or are not properly protected. Freewheeling diodes are appropriate for this function.

Contact switching for DC or AC

Relays of all kinds can be utilized to switch AC and DC loads. They are suitable in both DC and AC systems to safeguard AC and DC equipment. In addition, they are available with a broad range of coil voltages and an array of function modules. Logistics and warehouses are crucial to the evaluation of total cost. By using relays, you will be able to drastically reduce the cost of logistics. For instance, by using relays with multiple voltage inputs, you can cut down the size of your inventory.

Small size and low cost

The relays provide lower price with greater value and performance by delivering essential functions inside a compact housing. Despite the rising cost of raw materials they are affordable and effortlessly integrated in a range of circuits.

Connection to the terminal

There are a variety of sockets available to relays to satisfy the requirements of various scenarios, including those that require vibration. The compact design and various connector terminals can greatly improve the panel’s installation. There are numerous connections for terminals, like spring, screw and fork-type.

Certain relays are specially specifically designed to be used with PCB mounting. However, you can connect wires directly to pins if you are careful to prevent melting the case made of plastic that houses the relay.

Easy to set up and troubleshoot

Relays are simple to install by simply snapping onto DIN-rails. It is also possible to utilize jumping bars that make the connection more convenient. Troubleshooting typically involves the removal or isolation of the part, as well as an experiment on the bench to confirm the operation. The majority of relay models come with a switch at the top that permits technicians to turn the contacts off and on, even without electricity to the coil. This allows problems to be isolated on either the output or input side in a matter of seconds, and never require the removal of a single wire. removed.

Test button and Led indicator

Relays display the position of the contacts by using the use of an additional led. The state of the switch is evident to the naked eye. Certain types of relays have an additional test button. If it is activated, the contacts are activated. If it is removed, contact returns to previous condition.

High resistance

Relays have a very high resistance to voltage fluctuations. In RC modules, voltage spikes are compensated with the capacitor. In addition, they are able to withstand temporary overload on both the input and output side without loss of functionality.

Long-lasting and maintenance-free

Whatever the application or conditions Maintenance and repairs are essential and must be completed frequently. By using relays, you will significantly reduce the effort required. This makes the work simpler and faster, as well as more economical, and more secure. The life expectancy of an electrical good quality relay is about one million cycles of operation. It’s longer than other switches. But when it is used for rapid switching the lifespan of the relay is reduced. It’s important to consider this.

The disadvantages of relays

Relays can have disadvantages for both the system and users. They can be a problem for:

Contact wear

Because of their construction The relay modules are susceptible to wear and tear, both electrical and mechanical that should be considered as relay circuits are designed.

Use only for applications that are low-current.

Relays can be used for controlling voltages of 12 V to the 230 V range (generally) and also as switching currents ranging from 6- A and up A They are not suitable for switching high currents, like contactors.


They produce a lot noise when they activate or deactivation. It can be a nuisance in the event that you are using a lot of relays within the automation panel.

Slow operation

Relays are not able to switch quickly. The speed of operation for relays is restricted due to the inertia mechanical that surrounds the device. The speed of response as well as switching cycle are slower than transistors.

Change in character caused by age

The relay’s operation may be affected by ageing of the components as well as dust, which can cause false trips. As time goes by the springs as well as the parts of the relay get weak.

Poor performance when working with high inrush electrical currents as well as microelectronic circuits

Relays aren’t able to handle high inrush currents like contactors can. The efficiency of relays reduces when switching high-inrush currents.

The coil of a relay requires an extremely high amount of current to be energized. The high consumption of the coil is a drawback in certain microelectronic circuits due to the fact that they aren’t able to drive them directly without the addition of additional circuitry.

Poor performance in vibration environments

Many relays are specifically designed specifically for industrial use and have high-performance ratings. The conditions in railway vehicles vary significantly from the typical industrial application However, they are similar. High vibrations, frequently extensive temperature cycles, as well as corrosion-prone, oily and damp conditions are all stress elements that include relays. This could result in poor results when relays from industrial are employed in vehicles.