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A comprehensive guide to PCB Relay




An electrical component known as a printed circuit board (PCB) relay is often used to control the flow of electricity via electronic circuits. What is PCB relay? In simple terms, it can switch large currents or voltages in response to a low-level control signal. These relays are tiny, dependable, and adaptable in their operation.


A switch that is electromechanical but is installed on a printed circuit board is referred to as a PCB relay. It comprises a coil, a series of contacts, and a spring mechanism that moves the communications between their open and closed positions. The connections may be transferred between these locations by moving the spring mechanism. A low-level control signal provides the energy to power the coil, which, in turn, generates a magnetic field that either draws the contacts closer together or pushes them farther apart.

PCB Relay’s Internal Structure


The following elements make up the primary components of a PCB relay’s fundamental structure:




The coil consists of a wire wound around an internal magnetic core. When an electric current is sent through the coil, a magnetic field is produced, attracting the armature.




The contacts are fixed to the armature, a moveable component of the relay. The armature will move closer to the references to make a connection when the coil is activated.




The relay’s electrical connections are made at the terminals known as the contacts. They are either typically open (NO) or normally closed, depending on your preference (NC). The connections remain in their non-moving state when the relay is off since this is where they naturally rest.


Spring mechanism


The force required to move the contacts between their open and closed states is provided by the mechanism that utilizes springs.

Different kinds of PCB relays


PCB relays may be divided into various categories, depending on their construction, contacts’ design, and the application’s needs. The following are some examples of typical kinds of PCB relays:


Transmission Via Electromagnetic Relay


An electromagnetic field is used as the driving force behind the operation of this most fundamental sort of PCB relay. In addition to having a long lifetime, it can switch large currents or voltages.


Relay with Solid State


To switch the load, a solid-state relay makes use of electronic components. Because it does not have moving parts, it is more dependable than an electromagnetic relay and produces less noise.


The Reed Relay


A reed relay uses a pair of magnetic reeds to switch the load. It is compact and lightweight, and its switching speed is relatively quick.


Switching the Power


A power relay is a device that can switch large currents or voltages, often in the range of a few amperes to several hundred amperes. Its primary function is to protect circuits from overloading.


Signal Relay


It is the purpose of a signal relay to switch low-level signals, which generally fall within the range of a few milliamperes to a few amperes in current.



PCB relays provide a dependable and flexible method of switching power in electronic circuits, making them a crucial component. Because there are so many different kinds, they may be used in anything from factory robots to home entertainment systems. Switching strong currents or low-level signals, PCB relays can do it all. The downsides of relays, such as slow switching speed and mechanical wear, are usually outweighed by their benefits. PCB relays are still useful in developing and maintaining cutting-edge electronic systems.