Relays are often electrically operated and possess a set of input terminals. American scientist Joseph Henry invented the relay in 1835 to improve the old version of the electrical telegraph.
Where are relays used?
Relays are used to delay time functions and have also been used to time the delay open and delay close contacts. They are used to control high voltage circuits with the help of low voltage signals. They are also used to control high current circuits with the help of low current signals.
What are the different types of relays?
Relays are electrical devices used to delay time functions. They are different types of relays, including:
Based on pole and throw
Based on mechanical quantity
Based on operation principles
Polarised and non-polarised
Industrial applications of relays
Relays are often used for industrial purposes, and they are mostly controlled with the help of computers. In applications where relays are controlled with such devices, there is likely to be semiconductors like transistors. This causes the presence of voltage spikes.
A heavy-duty relay, called a contractor, is used to switch larger loads, such as motors. One reason for using relays is to assemble logical circuits for performing other functions. Relays are commonly used in automation equipment to isolate and protect the digital control system.