4 relay interfacing board isolated

1 | P a g e A n I S O 9 0 0 1 - 2 0 0 8 C e r t i f i e d C o m p a n y

4 RELAY INTERFACING BOARD ISOLATED Order Code RDL/4RB/13/001/V1.0

www.researchdesignlab.com

4 Relay Interfacing Board

The board has four relays driven by ULN2803 IC and

MCT2E IC for isolation purpose. The board works on 12V

but the input signal can come directly from microcontroller

output working at 3V or 5V to control relays. Each relay can

switch varierty of AC or DC high voltage, high current loads

working at 110V or 220V AC mains like lights, fans, motors

and such. The status of relay is indicated by individual LEDs.

Features

LED indication for relay and power supply.

AC or DC operating voltages.

No leakage current.

Design based on highly proven IC ULN2803 as driver.

Complete output isolation.

Eliminates costly isolation relays and wiring.

Applications

LED series and parallel connections.

Relay drive from external contacts.

Specifications

Parameter Value

Operating Voltage +12v dc

Current 8A




Pin Details

Pin Name Details

1 gnd Power supply ground

2 IN1 Connected to relay r1




Working

A relay is an electrical switch that opens and closes under the control

of another electrical circuit. In the original form, the switch is operated by an

electromagnet to open or close one or many sets of contacts. It was invented by

Joseph Henry in 1835. Because a relay is able to control an output circuit of

higher power than the input circuit, it can be considered to be, in a broad sense, a

form of an electrical amplifier.

Sugar Cube Relay

Despite the speed of technological developments, some

products prove so popular that their key parameters and design features

remain virtually unchanged for years. One such product is the „sugar cube‟




relay, shown in the figure above, which has proved useful to many designers

who needed to switch up to 10A, whilst using relatively little PCB area.

Since relays are switches, the terminology applies switches is also

applied to relays. A relay will switch one or more poles, each of whose contacts

can be thrown by energizing the coil in one of three ways:

1. Normally - open (NO) contacts connect the circuit when the relay is

activate d; the circuit is disconnected when the relay is inactive. It is also

called a FORM A contact or “make” contact.

2. Normally - closed (NC) contacts disconnect the circuit when the relay is

activated; the circuit is connected when relay is inactive. It is also called

FORM B contact or” break” contact.

3. Change-over or double-throw contacts control two circuits; one

normally open contact and one normally –closed contact with a common

terminal. It is also called a Form C “transfer “contact.

Sample Application

To view sample code and schematic click the below link:

http://researchdesignlab.com/index.php/interfacing-board/4-relay-interfacing-

board-isolated.html

http://researchdesignlab.com/index.php/interfacing-board/4-relay-interfacing-board-isolated.html





Board Dimensions

120.65mm

59.69mm

To buy this product click the below link

http://researchdesignlab.com/index.php/interfacing-board/4-relay-interfacing-

board-isolated.html

To view the complete datasheet of ULN2803 and MCT2E IC click the below

link:

http://forum.researchdesignlab.com/datasheet/uln2803

http://forum.researchdesignlab.com/datasheet/MCT2E



http://forum.researchdesignlab.com/datasheet/uln2803

http://forum.researchdesignlab.com/datasheet/MCT2E

4 relay interfacing board isolated

Documents