How to use a relay board – applications for electrical components

How to Use a Relay Board –
Applications for Electrical
Components

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Components

 A relay board is basically a printed circuit board on which there
are a number of relay switches. Before we get into applications, let’s
quickly define what a relay switch actually is.


Components

 In bare terms, a relay is simply that – a switch. It throws from one
state to another – the familiar 1 and 0 of electronics and binary code.
The relay is thrown from one state to another when an electrical
current is passed through it, or where an electromagnetic action flips
the switch mechanically.

Components

 In the latter case, which is the most common, the electromagnet is
powered by the electric current – and causes the relay switch to flip to its
alternate state..


Components

 This may either turn something on or off by depending on the logic of
the rest of the circuit will result in a positive action (like a circuit firing
up) or a negative one (like a trip switch being thrown and shutting down
a circuit).


Components

 The relay board is most commonly seen in the modern home as a
consumer unit (the thing your mum used to call a fuse board, but which
is now known as an RCD).


Components

 The electromagnet in an RCD unit fires when a current over a certain
level passes through it, causing the relay switch to turn that circuit off.
This prevents overload and dangerous currents being passed through the
wiring in a home, and dramatically reduces the cause of electrical fires in
older properties.

Components

 The relay board, then, is used where a range of circuits are to be
controlled by one signal; or where you need to control a circuit in
isolation from the control circuit. So you fire the control circuit, which
flips the relay switch (thereby disconnecting the control circuit) .


Components

The circuit you are controlling comes to life. When that circuit has lost
its current, the electromagnet controlling the relay switch lets go and it
click back to position 0, until the control circuit is fired again.


Components

Applications include the amplification of digital signals; and the
installation of for example, low voltage lighting control switches. The
relay board is present between the mains power source (which has a high
voltage) and the light switch, which uses low voltage wires for insertion
into partition walls.

Components

This is a fire safety and cost control measure – office partition walls are
frequently moved, so it makes no sense to hardwire them with expensive
mains wiring.
In many hobbyist projects, the relay board is there to act as a logic gate
for the functions of your circuits.

Components

 A switch is always either on or off (1 or 0) – but of course when you
have an array of switches you can quickly build complicated Boolean
procedures that allow you to do quite sophisticated things with even a
relatively small number of components.


Components

 Normally, Boolean AND is achieved by connecting a series of normally
open relays; while NAND and NOR are achieved when you connect
normally closed relays in specific ways.


Components

 Relay board components are manufactured in two states – normally
closed, or normally open.


How to use a relay board – applications for electrical components

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