Relay PCB

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How does a PCB Mount Relay Operate?

In the electrify circuit, you could get to notice the coil which is aligned with the contacts running along with the circuit.

When a current is permitting to flow, an electromagnet is made by the wire-wrapped coil, which creates a magnetic feld in the manufaturer.

It is may to open or shut the contacts by taking a magnetic feld that handle go through a metal plate that is linking to the armature.

The break count, pole count, and throw count of the relay possible used to control the contacts of the relay in various ways.

Main Difference

What is the Main Difference Between a Relay PCB and a Relay Module?

A Relay PCB is taking responsible for generating variations in voltage as to operate circuits either go through electromagnetic conductivity or by employing a solid-state mechanism.

A relay module is forming of several Relay PCBs, as well as additional circuit components, which include equipment like resistors, transistors, and diodes.

The major difference between a Relay PCB and a relay module is that in a Relay PCB, it’s an individual relay can only use a single circuit.

If you have several relay PCBs that you need to handle, you need to employ numerous circuits at the same time.

Can You Purchase Used Relay PCBs?

Most of the manufacturers supply used Relay PCBs as well as used parts of the Relay PCB and you can buy them for sure, Anyway, their condition needs to be verifed, and you should make sure that you do not get ripped off.

If an old or used Relay PCB is still operational, you may reuse it by simply desoldering it from its old circuit board.

You are possible to have a further resolder the old Relay PCB onto a new board since they are designed to resist severe soldering temperatures.



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relay PCB

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relay PCB

Venture relay PCB allows to control a remote device. It is not necessary to be near the device to make it work and change contacts easily. Relay PCB is an output device which come in a whole host of shapes, sizes and designs, and have many uses and applications in electronic circuits.

Our relay PCB truly works well at high temperatures. This is activated with low current, however it can activate large machines of great power. With a single signal you can control several contacts at once and can also switch direct current or alternating current.

relay PCB

Venture produces a wide array of relay PCB that will suit to your specifications and requirements. All the relay PCB we provide will match all your PCB needs. Venture Electronics, has been a professional PCB design & fabrication and PCB assembly.

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relay PCB

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Relay PCB: The Ultimate FAQ Guide


Before choosing your next relay PCB, read this guide.

It covers everything you need to know about relay PCBs, from components, features, specifications, working principle, operating voltage to components, among other critical aspects.

So keep reading to learn more.

What Is Relay PCB?

A relay PCB is a circuit system with electromechanically or electronically controlled switches issuing voltage variation.

You identify input contacts used for either singular or multiple signal control alongside operating contacts.

Relay PCB

Relay PCB

You find relay PCBs useful in circuit control especially when employing a signal with low and independent power. Additionally, a relay PCB is useful where you have to control multiple circuits with a single signal.

Relays allow you to refresh incoming signals from a circuit by transferring it via other circuit. You can employ both movable and immovable parts in the opening and closing of circuits with a relay PCB.

Conventional relay PCBs employ electromagnets to control the opening and closing of circuits whereas modern relay PCBs employ semiconductors.

Is There Difference Between Relay PCB And Relay Module?

A relay PCB constitutes voltage variation via electromagnetic conduction or solid state system to control circuits.

While you can employ a single relay to control a single circuit, you need multiple relay PCBs for multiple circuits.

A relay module constitutes multiple relay PCBs alongside other circuit components such as resistors, transistors and diodes.

A relay module is useful where you need to control multiple circuits stemming from a single circuit.

Which Are The Different Types Of Solid State And Electromechanical Relays Used In Relay PCB Assembly?

Electromechanical relays employ magnetic force to control the opening and closing of contacts.

Contrarily, solid state relays do away with movable parts instead employing semiconductors in the switching process.

You find the following types of electromechanical relays used in relay PCB assembly:

General Purpose Relays

General purpose relays are electromechanical relays that employ a magnetic coil with either DC or AC supply voltage. You can find these relays with voltage values between 12V and 230V with current amounts from 2A to 30A.

General Purpose relays are cost-effective with low maintenance requirements. You can support various configurations of switches with this relay that is easily replaceable.

Machine Control Relays

This relay PCB also employs magnetic coils in their structure with heavy duty capabilities suited for starter control in industrial equipment. The machine control relays are more durable and expensive compared to general purpose relays.

Reed Relays

These relay PCBs are small and efficient employing a single contact with NO configuration and fast switching capability.

You find these relays enclosed in a glass casing ensuring protection of the contacts from external elements such as contaminants.

A reed relay PCB has faster and reliable switching capabilities and the contacts offer you a long service life.

A magnet opens and closes the contacts typically coated with material with low resistance to enhance conductivity.

Some of the solid state relays you employ in relay PCB assemblies include:

Zero-Switching Relays

On application of the control voltage, this solid state relay turns ON moving the load voltage towards zero. Contrarily, the relay turns OFF on removal of the control voltage with a current figure close to zero.

Instant ON Relays

The instant ON relay PCB activates the load upon confirmation of a pickup voltage. These relays allow load activation to ON status anywhere within the wave formation.

Peak Switching Relays

The peak switching relay is ON upon reception of a control voltage with a peak load voltage. When you remove the control voltage and the load current fall to almost zero, the peak switching relay turns OFF.

Analog Switching Relays

An analog switching relay works within a defined range with an unlimited possibility of output voltages.

These relays have a synchronized circuit that regulates the output voltage relative to the input voltage.

Types of Relay

Types of Relay

What Are The Main Components Of PCB Mount Relay?

A PCB mount relay typically encompasses two circuits namely, the energizing and contact circuits. The following are the main components of a PCB mount relay:


The frame consists of a rigid structure that holds and physically supports the relay structure.


You form the coil by winding a wire over a metal piece to induce an electromagnetic field.


Constitutes the movable part of a relay allowing contact opening and closing. A return spring ensures the armature returns to its former position after every action.


The voltage transfer occurs in the circuit via the contacts through opening and closing.

You find the coil positioned on the energizing circuit with the contacts along the contact circuit. When you allow a current flow, an electromagnet forms via the wire wound coil forming a magnetic field.

The magnetic field acts on a metal plate attached to the armature allowing you to open or close the contacts. You can have different contacts influenced by the break count, pole count or throw count of the relay.

How Does Electromechanical Relay PCB Assembly Vs. Reed Relay PCB Assembly Compare?

You use electromechanical and reed relay PCB assemblies for management of power for control systems using resistive and inductive loads.

You can directly attach these relays to a circuit board with a compact design.

An electromechanical relay PCB assembly encompasses a coil which magnetizes upon flow of current, an armature and contacts.

The magnetized coil creates a magnetic field which induces motion from the armature causing the contacts to open or close.

On the contrary, Reed relay PCB assemblies have an enclosed tube of glass with wound coils containing the reeds and contacts.

Allowing current through the coil of a reed relay assembly, creates a magnetic field that moves the contacts closing them.

You experience an extended service life with the reed relay PCB assembly thanks to the impressively fast switching times.

Switching times in a reed relay construction typically takes less than a microsecond finding use in starter motors, solenoids and contactors.

Why Are PCB Mount Solid State Relays The Best Option For Industrial And Commercial Applications That Needs Devices Having Smaller Footprints?

When constructing a solid state relay PCB assembly, you consider the operating conditions and the mounting approach.

Essential conditions include the load and surge current, the working temperature and airflow, and the size and spacing requirements.

Spacing is essential due to dissipate excess heat caused by large current transactions.

If undealt with, these dissipations can negatively impact the working of other relays in an assembly.

Industrial and Commercial Applications with smaller footprints require solid state relay PCB assemblies for the following reasons:

  • Such relay assemblies offer you a long and useful service life.
  • Since you have no movable contacts, you experience no bouncing or arching of contact thereof.
  • A solid state relay PCB assembly offers you zero-crossing capability.
  • The power input when using a solid state relay PCB assembly is low.
  • You achieve high resistance to vibrations and shocks when using a solid state relay.
  • Since you employ either single or dual in-line package mountings with this assembly, you achieve more space savings.

What Are The Parameters To Consider During The Design And Fabrication Of Solid State Relay PCB?

When designing and fabricating a solid state relay PCB the following parameters are important:

  • Required activating input voltage which you subject to the input circuit.
  • Amount of current
  • Output voltage and current of the output or load-switching circuit.
  • Decision to employ AC or DC voltage.
  • Resistance or voltage drop influencing the current output.
  • Thermal parameters such as thermal resistance which ensure low heat dissipation and effective control.
  • Use of zero crossing hardware in turning voltage ON or OFF with a zero AC voltage.

How Do You Connect The Electromagnetic Relay Terminals To Relay PCB?

Connecting the electromagnetic relay to the circuit board involves configuring the pin terminals in one of the following ways:


You supply negative voltage to one coil end connecting to the terminal causing a power supply to the other coil.


Similarly, another voltage supply to one coil end results in power supply to the other end.

NO – Normally Open

Upon receipt of enough voltage to power up, the relay power up on connection. In the absence of power, the PCB is OFF and ON when power gets to the relay.

NC – Normally Closed

You have the terminal connected to the PCB when power gets to the relay. In the absence of power to the relay, the device stays ON turning OFF upon receipt of power.

Relay Terminals

Relay Terminals

What Is The Soldering Method Used For Mounting Relay PCB Components?

Soldering is the process of attaching components and board members to the printed circuit board.

When attaching these components you either surface mount them or attach them via through-holes.

When mounting relay components, you employ through-hole technology where you fasten their leads in plated holes.

Through-hole technology offers you a firmer board connection ensuring you maintain board attachment amidst shocks and vibrations.

What Are The Relay PCB Design Requirements?

You find further design changes in the development of relays to meet the market demands of smaller gadgets.

Consequently, you find many electromagnetic relays made to directly attach to the board surface.

When designing the relay PCB, you need to consider the following:

  1. The mounting process of the relay with regard to the soldering process and heat application employed. You need to select a mounting procedure that does not hamper the internal system of the relay via distortion.
  2. For the relay mounting, you require PCB material derived from glass and paper based epoxy. These materials should be at least 1.6 mm thick to support the relay.
  3. On the other hand, you need to have copper circuitry with a thickness of between 35 and 75 micrometer. Providing such a range of thickness ensures efficient thermal management regardless of the relay size.
  4. You observe a difference in performance of the relay PCB assembly when subjected to environments of heat and magnetic fields.
    Therefore, you need to consider the position of the relays relative to sources of such interference such as semiconductors and transformers.
  5. In design efforts for the relay PCB assembly, you have to consider the impact of physical shocks such as vibrations.
    You accommodate this in your mechanical design by mounting the device to absorb shocks and vibrations perpendicular to the armature movement.

How Do You Prevent The Interference Of Heat And Electromagnetic Fields In Thermal And Electromagnetic Relay PCB Assembly?

An electromagnetic relay has an electromagnet that creates a magnetic field upon current supply before inducing armature movement.

The movement of the armature guides the process of the circuit’s switch opening and closing.

Alternatively, you have a reed relay with two magnetic strips referred to as reeds enclosed in a glass tubing.

Current flow magnetizes the coil transforming the reeds into an actuator with an edge contact initiating the switching process.

When the surrounding temperature exceeds the required minimum, the contacts in a thermal relay assembly switch up.

Switching of the contacts ensures protection of the PCB device from overloading resulting from the thermal change.

When used on a PCB assembly, some relay PCB assemblies have seals to enclose them protecting them from electromagnetic interference.

Some boards have components such as transformers that generate external electromagnetic fields which interfere with the performance of relays.

What Is The Meaning Of NO And NC In Relay PCB?

Relays are essentially switches and you can switch poles via contact movement through current conduction in the coil.

When you pass current in the relay coil, you can initiate two positions: Normally Open (NO) or Normally Closed (NC).

Your relay is Normally Open upon activation of the relay enabling the connection of the circuit via contacts.

When you deactivate the relay by cutting current supply, you detach the contacts disconnecting the circuit.

You can also refer to a Normally Open (NO) circuit as a Form A or make contact.

Additionally, reference as an early-make contact suffices due to contact closing before full switch engagement.

A Normally Closed (NC) circuit has the contacts separating upon relay activation with a current supply.

When you cut current supply to the relay, the contacts connect completing the circuit.

You refer to the Normally Closed (NC) circuit as the Form B or break contact.

Furthermore, reference to this circuit as a late-break contact suffices since it maintain closed contacts till full disengagement of switches.

Do Relay PCBs Have Standard Switching Capacity?

When rating the switching capacity or load of a relay PCB assembly, you use the voltage and current parameters.

The voltage here is the terminal load voltage you experience in an open relay circuit.

Contrarily, the current refers to the terminal current flowing through the load and relay when you close the circuit.

You provide both the minimum and maximum switching capacities for switches and hence relays PCB assemblies.

Having a minimum switching capacity is essential in ensuring the relay PCB assembly offers you a long and useful service.

You find that upon continued use, matter accumulates on the armature contacts of the relay PCB assembly.

Where you have a minimum current amount, it burns the matter accumulation at the armature contacts upon relay circuit closure.

However, this is difficult for armature relay PCB assemblies of electromechanical nature.

For reed relay PCB assemblies, you enclose the contacts in a glass tubing with noble gas preventing accumulation of material.

For solid state relay and field effect transistor relay PCB assemblies, absence of moving parts means they are unaffected.

Which Are The Applicable Relay Configurations On Relay PCB?

Operation of relay PCB assemblies is similar to switches and consequently, you can open and close circuits via coil conduction.

You describe the opening and closing of these circuits in two ways: Normally Open (NO) and Normally Closed (NC).

The relay configurations you can apply in a relay PCB assembly will encompass a mix of NO and NC circuits.

While there are more than twenty configurations, you find the following more common:

SPST – Single Pole Single Throw.

With this configuration, you have a pair of terminals you can connect or disconnect. Additionally, the two terminals for the coil provide a total of four.

Determining whether you have a pole Normally Open or Normally Closed is vague. However, you use the identifications of SPNO and SPNC to distinguish the pole position.

SPDT – Single Pole Double Throw.

You have a single terminal offering common connection to the other two with this configuration. When you consider the coil terminal pairing, you have a total of five terminals.

DPST – Double Pole Single Throw.

The DPST has a double terminal pairing corresponding to a pair of SPST relay configuration with a single coil actuator. You achieve a six terminal count when you consider the coil terminal pairing with Form A or B poles.

DPDT – Double Pole Double Throw.

In this configuration, you find a row pair of terminals with change-over corresponding to a pair of SPDT switches.  You can also have a single coil act as an actuator for the relays with a total of eight terminals.

What Is The Operating Voltage Of Relay PCB?

You find relay PCBs with a wide range of operating voltages depending on the application and source.

There are relay PCB assemblies with operating voltages from 5V to over 230V.

The operating voltage is essential for the activation of a relay PCB assembly. You find many relay PCB assemblies employ DC voltage for their operating voltage.

Common relay PCB assemblies employing DC operating voltage includes relays delivering small signals or with low voltage power.

However, relay PCB assemblies such as contactors and mains control employ AC operating voltage.

You note switching pins of the relay as well as contact pins assigned maximum and minimum voltage and current parameters.

You find the information regarding the mentioned parameters provided on the relay packages.

The information provided on the contact can read as 5A@250VAC and 10A@12DC.

This signifies the operating current and voltage values and voltage source which you have to operate within.

Where you have a lower voltage source, you can employ a higher current value in compensation.

However, ensure you do not overload the relay to prevent destructive burn out to the circuit and related components.

Is The Operating Voltage Of Relay PCB In DC Or AC?

The operating voltage of a relay PCB assembly can be DC or AC depending on the application. You find many relay PCB assemblies with DC operating voltages ranging from 5V to 24V.

Circumstance where you have DC operating voltages include relays with small signal and low voltage power.

You have AC operating voltages where you require mains control and in the case of contactors.

However, regardless of the operating voltage type, you have maximum and minimum voltage and current values.

You need to operate within the set limits to prevent damage by burn out of the relay PCB assembly.

Color Relay PCB

Color Relay PCB

How Does High-Voltage Relay And Overcurrent Relays Of Relay PCB Compare?

A relay PCB is useful where you have regulatory concerns between a circuit with high voltage and another with low power.

Furthermore, unlike switching applications involving transistors, relay PCBs offer you with galvanic isolation.

The relay PCB assembly is typically compact with a low operating voltage.

However, you have relay PCBs with high operating voltage designed for applications with high value voltage and current parameters.

You find high voltage relay PCBs employed in applications such as mains controls and contactors.

Conversely, overcurrent relays are useful when discontinuing flow paths for high currents in the wrong circuit direction.

Why Is Spacing Important In High Voltage Relay PCBs?

High voltage relay PCBs are assemblies with high operating voltage values usually exceeding 30 VAC or 60 VDC.

With such PCBs, you need to carefully consider your spacing needs during board design to prevent failure.

Moreover, where your PCB assembly has a large component count, spacing becomes very important.

Procuring adequate space requirements for your high voltage PCB is essential in intervening on issues with signal integrity.

Additionally, when you provide sufficient spacing between circuit components when employing a high-voltage relay you avert arc discharge.

While providing enough spacing for a dense PCB is difficult, it is vital for a successful performance.

When operating a high voltage relay PCB assembly, a potential difference can arise between conductive components.

Where the resulting potential difference is in excess of the breakdown voltage, it results in an arc.

An arc discharge can be destructive resulting in component failure and board failure in general.

Furthermore, an arc discharge has shock potential which can harm any board user who gets in contact.

What Is Clearance And Creepage And Why Are They Important Parameters In Power Relay PCB?

When applying spacing protocols on your high-voltage and power relay PCB assemblies, you apply two aspects: clearance and creepage distance.

These two spacing requirements allow you to mitigate the chance of board failure resulting from arc discharge and signal interference.

Clearance refers to the minimum distance over air you need to fashion conductive components on your PCB.

For power relay PCB assemblies, you need enough clearance to prevent arc discharge between conductors resulting from an overvoltage.

You employ different clearance measurements on your power relay PCB depending on the board material, operating voltage and environmental factors.

Since clearance is a measure through the air, you find environmental factors very important.

A major environmental factor is humidity whose moisture content breaks down the air voltage increasing the chance of arcing.

Additionally, accumulation of dust between conductors can form an electrical path reducing the spacing between conductive elements.

Creepage is also in reference to the distance between conductive elements on a power relay PCB assembly.

However, you measure the minimum distance over the non-conductive layer rather than the air distance.

You also observe environmental factors and the board material influences creepage on power relay PCBs.

Humidity and accumulation of dust have the same effect of truncating the distance between conductors similar to clearance.

Implementing creepage on a high density PCB is difficult due to the space constraint making track layout alteration improbable.

Nonetheless, you can introduce slots to separate conductive tracks or employ vertical insulating elements to considerably augment creepage distance.

How Do You Determine Trace Width Of High Voltage Relay PCB Design?

Trace width refers to the distance across a conductive track on a printed circuit board.

For a high voltage relay PCB, the challenge is in determining the trace width to achieve effective dissipation of heat.

Consequently, you find the choice of conductive material for a high voltage relay PCB track influences the board’s temperature rise.

Copper offers decent tolerance to heat buildup with its high melting point and low resistance.

When determining your high voltage relay PCB trace width design, ensure the board’s temperature rise doesn’t exceed 10°C.

Where the conductive tracks build up heat to high temperature values exerts pressure on the board’s cooling mechanisms.

You find the IPC 2152 standard essential in designing the conductive tracks for your high voltage relay PCB.

The standard provides different formulae for determining the current limits associated with a specified temperature rise.

However, you find the impact of controlled impedance in the routing endeavour missing. From these formulae, you can derive a current and trace width table useful in designing a high voltage relay assembly.

When using a trace width and current table, you can provide a maximum value for current flowing through your traces.

Subsequently, you can use this figure to determine the adequate trace width you require for effective impedance control.

A high voltage relay PCB can display material change on temperature buildup resulting from a high current flow.

The insulating layer encounters electrical and mechanical breakdown that can be damaging without mitigation.

You can furnish the trace width to be receptive to a wide operating temperature range instead of a particular value.

Equally important, you can determine appropriate thickness by calculating using the board’s copper weight.

What Property Of Relay PCB Material Indicates Its Electrical Insulation?

Electrical insulation of a relay PCB material refers to its tendency to resist electrical charge flow.

You use a material’s comparative tracking index (CTI) to determine its electrical insulation quality.

CTI is voltage value you determine from conducting a test that establishes the breakdown point of a material surface.

You have six known classifications providing a material’s voltage breakdown value from 0 to 5 in descending order.

Materials in category 5 have the least CTI with poor electrical insulation with a breakdown voltage value lower than 100 V.

Contrarily, materials in category 0 have breakdown voltage of over 600 V offering you the best option.

Which Are The Two Safety Standards Crucial In Determining The Best Relay PCB Material To Use?

When determining the best relay PCB material, you find two standards essential in the selection process.

These standards reference the material’s breakdown voltage and hence its performance under high voltage operations.

IPC-2221 Voltage And Spacing Standards

The IPC-2221 provides stipulations in reference to the relay PCB assembly’s clearance and creepage parameters.

You find mentioned in the standard the material requirements and trace factors necessary for a high quality board.

Furthermore, you can determine the least spacing for your relay PCB for effective performance using this standard.

You can do this by extracting a calculator for determining high voltage clearance from the standard.

IEC-60950-1 (2nd Edition)

The second edition of the IEC-60950-1 covers relay PCBs employing a DC or AC voltage source. You find stipulations guiding adequate board spacing to prevent signal interference and arcing that can cause damage and harm.

What Are The Applications Of Relay PCB?

Relay PCB assemblies find a wide application range due to the many different available configurations.

You find relay PCBs employed in switching applications including for heaters, motors and lamps.

Common applications of the relay PCB are:

Relay PCB Assembly

Relay PCB Assembly

Industrial Equipment

You employ relay PCBs in industrial equipment such as welders, machine tools, molders and robots as a control device.

The relay PCBs function in switching lines and control mechanisms.

Household Equipment

Relay PCBs such as power relays find use in households to make garage shutters and luminary equipment.

You also use relay PCBs to control compressors, motors or pumps in refrigerators and air conditioners and washing machines.

Power Supply Equipment

You employ relay PCBs to control power supply in equipment such as UPS and switching power supplies.

Security Devices

A PCB relay can function as an alarm and employed in warning systems such as anti-burglary equipment and gas detectors.

Test and Measuring Equipment

You can use the relay PCB in conducting power switching and input and output switches. Some of the devices with thee relay PCB assemblies include measuring devices, semiconductor testers and oscilloscopes.


Automation has made life simpler by making complex processes easier and other common processes more efficient.

You employ relays in such automation aspects such as controlling robots and other functions in factory applications.

You also find automation of utility meters in households and commercial building such as gas meters and water meters.

Many modern buildings have also implemented automated features such as lighting and air-conditioning thanks to relay PCB assemblies.

Amusement Equipment

Amusement parks have different machines that put smiles on young persons and even adults. These machines such as game balls, lending machines and dispenser employ relay PCBs for status output and signal switching.

Can You Reuse Old Relay PCB Assembly?

You can reuse old relay PCB assembly that is still functional by desoldering from its former circuit.

Since relay PCBs can withstand extreme soldering, you can resolder the relay PCB assembly to a new circuit.

Furthermore, you can usefully employ parts of an old relay PCB such as the coil windings contacts and fasteners.

For instance, coil windings can be handy in different circuits’ layouts to make jumper wires.

What Is Contact Life Of Relay PCB?

In relay PCB assemblies, the relay contacts determine how long the relay will be effective in its operation.

Wearing out of the contacts results in a replacement of the contacts or the whole relay assembly.

When talking about contact life of a relay PCB, you consider its mechanical and electrical life. The mechanical life of a relay PCB refers to the total contact operation count in the absence of electrical power.

The operations spoken of in the contact life description of the contacts are opening and closing operations.

You find relays can offer you an extended mechanical life reaching about a million operation cycles.

An electrical life of a relay refers to the total number of contact operations with electrical power at a specified rating.

The electrical life of contacts is typically shorter than the mechanical life ranging from 100,000 to less than a million cycles.

How Do You Classify Relay PCBs?

There are many ways you can classify relay PCB assemblies such as basing on the construction, contacts, function and mounting.

You can have relays with or without contacts depending on the application.

For instance, for an electromagnetic relay PCB assembly, you can have single or double pole single-throw contacts.

Furthermore, you have relay PCBs that are surface mount or those with discrete mounting techniques.

When classifying relays according to their construction, you find some relays built for flux protection and others sealed.

Single-side and latching relays turn on or off or remain on or off upon receipt of an input signal respectively.

Common classifications of the relay PCB includes:

Electromagnetic Relays

An electromagnetic relay encompasses electrical and mechanical parts which combine to form a magnetic components that moves mechanical contacts.

A wire wound coil has current flown through upon which it magnetizes causing the opening or closing of contacts.

When you using an electromagnetic relay, you can employ either DC or AC operating voltage. Common types of electromagnetic relays include the attraction type and induction type.

Solid State Relays

Solid state relays employ semiconductor components rather than movable mechanical parts in the switching application. These relays have a higher power gain compared to the electromagnetic relays due to lower control energy than output power.

Solid state relays have faster switching speeds than other relay PCB assemblies and include transformer-couples relays and photo-coupled relays.

The lack of contacts in these relays ensures minimum noise levels and extended useful service life.

Hybrid Relays

Hybrid relays include both electronic aspects and electromagnetic aspects in parallel operation in its configuration.

You find the electronic aspect for the input where rectification occurs and electromagnetic build for the output part.

A hybrid relay mitigates the power wastage observed in solid state relays through heat dissipation.

On the other hand, using a hybrid relay eliminates the electromagnetic relay problem of arching at the contacts.

Thermal Relays

Thermal relays function by responding to heat changes by moving the contacts’ position thus enabling switching operations.

When you have a visible temperature change, the contacts respond changing their position relative to the temperature change.

You find thermal relays employed as control elements in protection of motors and bimetallic aspects such as temperature sensors.

How Does Solid State Relay PCB Work?

Solid state relays switch load signals via employing electronic components instead of mechanical contacts. You find three circuits with a solid state relay PCB namely, the input circuit, control circuit and output circuit.

The following steps define the working of a solid state relay PCB:

  1. An electric charge supply turns the device ON.
  2. When the flow of current reaches the input circuit, it activates the photocoupler.
    Thereafter, a transfer of the electric signal to the output circuit follows.
  3. The output circuit has a switching element that then turn ON.
  4. At the same time, the load current flows igniting the lamp to ON state.
  5. The switch then turns OFF.
  6. As a result, the photocoupler turns OFF, followed by the output’s trigger circuit and the switching element.
  7. The lamp turns OFF when the switching element deactivates.

What Are The Features Of MOSFET Relay PCB?

MOSFET Relay PCBs are semiconductor relay assemblies that employ transistors in their outputs.

These relay PCBs have no contacts and find use in varied switching applications such as testing and measuring equipment.

MOSFET Solid State Relay PCBMOSFET Solid State Relay PCB

MOSFET relay PCBs have the following features:

Compact And Lightweight

The MOSFET relay PCBs are ultra-small and light due to the implementation of miniaturization in their construction.

You find small outline packages employed for these relay PCBs.

Reduced Leakage Current

You experience a reduced leakage current with MOSFET relay PCBs due to augmented resistance to surges from external sources.

You find the leakage current amounts to as little as one nano-ampere when OFF.

Extended Life

MOSFET relay PCBs lack movable parts in the form of contacts instead employing electronic signals in its operation.

This ensures there is no wear and tear resulting in an extended service life.

Low Drive Current

When operating the MOSFET relay PCBs under normal conditions, their drive current ranges from only 2 mA to 15 mA.

Furthermore, you will find some MOSFET relay PCB application with as little as 0.2 mA in drive current.

High Insulation

The MOSFET relay PCB offers enhanced insulation with regard to noise reduction as a result of zero switching noise.

Accurate Small Analog Signal Control

When using the MOSFET relay PCB, you find the dead band to be smaller than a triac for instance.

Consequently, you find minimal distortion during conversion of small analog signal’s input wave formation to an output formation.

Low Noise Production

The working of a MOSFET relay PCB is quiet with no noise generation due to absence of movable parts.

Greater Impact Resistance

The resistance to impacts such as shocks and vibration of MOSFET relay PCBs is impressive. You credit this to the absence of movable parts and use of molding to construct the relay’s internal structure.

How Do You Test Relay PCB?

Testing a relay PCB allows you to determine its operating condition by identifying any associated problems.

When carrying out a test on a relay PCB, you evaluate the relay parts establishing any anomalies.

You can test a relay PCB by conducting the following checks:

Testing Resistance Of The Coil

The coil resistance is essential in determining the operating voltage and current values for a relay PCB.

You can use a multimeter to establish the coil resistance by calculating for the voltage and current.

Testing Contact Resistance

The resistance of the contact refers to the resistance value of the normally closed and movable contacts.

When checking for this resistance, you use a multimeter set to resistance mode which has to be zero.

Testing Pull-In Voltage And Current

When you put a voltage set the relay via regulating supply power, you test for the pull-in voltage and current. Thereafter, you monitor the supply power using an ampere meter while gradually increasing the voltage.

You then record the pull-in voltage and current upon production of a pull-in sound. You should repeat the process severally to provide a more accurate outcome.

Testing Release Voltage And Current

The test process for release voltage and current share similarities with that of pull-in voltage and current.

As you pull-in the relay, turn down the power supply voltage until sound production and record the voltage and current values.

You find the release voltage is typically about ten to fifty percent of the pull-in voltage. Where you have a very small release voltage, you encounter performance issues with your relay.

What Is The Difference Between 4 Or 5 Pin Relay PCBs?

You find the difference between a 4-pin and 5-pin relay PCB lies in the circuits under control. You employ a 4-pin relay for the control of a single circuit while a 5-pin works with two circuits.

4-Pin Relay

In a 4-pin relay, you find two coil control pins and another pair for single circuit switching power.

You have two types of a 4-pin relay namely: Normally Open and Normally Closed.

When you activate the coil, you find the circuit switches power ON when Normally Open. When you activate the coil for a Normally Closed 4-pin relay, the circuit power switches OFF.

4-Channel Relay PCB Design4-Channel Relay PCB Design

5-Pin Relay

You have a pair of coil control pins and a three-pin power switch for a circuit pair in a 5-pin relay.

The pin connections are both NO and NC and a coil activation switches power from the latter pin to the former.

What Is The Difference Between Single And Double Winding Latching Relay PCB?

A single-winding latching relay maintains the operating condition of the relay magnetically when you input a set pulse.

However, resetting the input pulse subjects the relay in a reset condition.

For a double-winding latching relay, inputting a set pulse to the coil, maintains the operation condition magnetically or mechanically. However, when you input the pulse to the reset coil it puts the relay into a reset.

What Are The Operating And Storage Conditions For Relay PCBs?

When operating and storing the relay PCB, you have to adhere to certain guidelines.

When this happens, you ensure effective performance and an extended serviced life from your relay PCB.

The following guidelines are useful when operating or storing relay PCBs:

  1. You need to maintain the temperature, pressure and humidity at room conditions and avoid direct sunlight. Excess humidity and temperature can cause oxide formation on the contacts resulting in potential failure.
  2. Furthermore, having increased moisture content can accelerate the effect of tracking and result in insulation failure for the relay PCB. Furthermore, humidity can also cause a huge potential difference in the relay resulting in an arc discharge.
  3. You shouldn’t also use relay PCBs is environments with corrosive and flammable gas. When operating the relay PCB in such conditions, you may experience explosions or fires due to switching.
  4. Additionally, dusty environments are unfavorable as the cause a particulate buildup on the contacts. When particles accumulate on the contacts of a PCB relay, they can fail during operation.
  5. External magnetic fields are also damaging to the relay PCBs when operating or storing especially for electromagnetic relays. When these fields are strong, you can develop tracking or insulation failure and arc discharge during operation.
  6. You should also avoid excessive vibrations and shocks during operation and storage of relay PCBs. Such abrupt movements can make the relay PCBs faulty in their operation or physically impair them.

Can You Use Coating On Relay PCBs?

Using coating on a relay PCB is a process requiring care to ensure the coating doesn’t infiltrate the relay PCB.

Coating agents can damage the internal pats of a relay PCB resulting in failure during operation.

However, you can seal the relay PCB in plastic where you employ coating and avoid the use of silicone. Epoxy and urethane derived coatings offer you good insulation for your relay PCB instead.

With the information in this guide, I am sure you can choose the best relay PCB for all your applications.

In case you have any questions or inquiry, Venture Electronics team is here to help – contact us now.

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