A brief presentation about the Relay, an electronic switching device. A relay is an electrically operated switch. Current flowing through the coil of the relay creates a magnetic field which attracts a lever and changes the switch contacts. The coil current can be on or off so relays have two switch positions and most have double throw (changeover) switch contacts. Duration Time: 5 minutes.

1. Relay
Name: S.A. Muktadir Samrat
ID: 153001002
Department: EEE
Batch: 1503

2. 2
Contents
● Definition
●History
●Basic Design and Operation
● Types of Relay
● Applications
●Reference Links
●Conclusion

3. 3
Definition
A relay is an electrically operated switch. Current flowing
through the coil of the relay creates a magnetic field which
attracts a lever and changes the switch contacts. The coil
current can be on or off so relays have two switch positions
and most have double throw (changeover) switch contacts.

4. 4
History
A simple device, which is now
called a relay, was included in
the original 1840 telegraph
patent of Samuel Morse.
In 1833 Carl Friedrich Gauss
and Wilhelm Weber developed
an electromagnetic relay.

5. 5
Basic Design and Operation
As shown in the figure, CT
(Current Transformer)
secondary winding is directly
connected to the Relay coil.
Under normal condition, the
current through the Relay coil
is not sufficient enough to
pull the plunger and close the
circuit of Breaker Tripping
Coil. Two trip coils are
normally provided Circuit
Breaker.

6. 6
Types of Relay
● Electromagnetic Relays
● Solid State Relays
● Hybrid Relay
● Thermal Relay
● Reed Relay

7. 7
Applications

8. 8
Reference Links
➔ https://electronicsclub.info/relays.htm
➔ https://etrical.blogspot.com/2016/09/basic-principle-of-relay-opera
➔ https://en.wikipedia.org/wiki/Relay
➔ http://denkovi.com/usb-eight-channel-relay-board-for-automation

9. 9
Conclusion
Have You any Questions??

10. 9
Conclusion
Have You any Questions??