Most of the time, people turn on an electric gadget in their homes and do not think twice about the electricity that flows through wires. Neither do they think about what it takes to control that electricity. Control of the electric current is achieved by making use of power relays. To simplify, these relays are electronically operated switches. They help to control power circuits.
These days, many of the relays used are called solid state relays. However, by going back in history, we will see that the first relays used were electromagnetic or electromechanical relays. The history of relays can be traced back to Joseph Henry. He invented the electromagnetic relay. His true interest was in electricity but it was this interest which led him to create a make and break switch. His initial invention was eventually used by Samuel Morse to deliver messages through several kilometers of wires.
Advancement has been made in the creation of relays. Since Henry first created the electromagnetic relay, another type of relay has also been made available. These days, we can also make use of solid state relays. Also referred to as SSR, the Solid State Relays are used to control power circuits that do not have any moving parts. Instead of using mechanical means, an SSR uses a semiconductor device in order to make the switch. While the electromagnetic or electromechanical relay has been around for a long time, there are advantages to using the SSR.
Speed is one major advantage. Solid state relays can achieve the switch at a much faster rate than the electromechanical relay. The speed of the SSR is so fast that it is measured in microseconds to milliseconds. Another advantage to SSRs is its durability and resistance to wear and tear.
Electromechanical relays have moving parts which will eventually wear out with continued use. Such a concern does not exist when using the SSR. Because it has no moving parts, then there are no parts which can become worn out. This also adds to the SSR's reliability. It will continue to function with the same efficiency as when it was first used. This also means that the operation is cleaner and smoother. There will be no concern about parts not responding in the expected manner. Plus, electromechanical relays could cause sparks as the parts move. There is no danger of that happening when using an SSR.
Another advantage of the SSR has to deal with noise. As the switching occurs, there is no noise created. As such, work environments are not affected by any additional "noise pollution" that an electromechanical relay may cause. With an SSR, you can be assured of absolute silent as the switch occurs.
Artice Source: http://www.articlesphere.com
Related Articles in Science
People interested in the above article are also interested in the related articles listed below:
Archaeoastronomy is the study of how folks in the past accepted the phenomenon occurring in the sky, how they utilised the phenomenon and what part the sky played in the culture of these people. Archaeoastronomy can be said to be closely associated the historical astronomy. It is also related with the historic records of heavenly events which can often be used to answer astronomic Problems.
There are lots of predictions depending on which on 21st December 2012 the world will end. This date is meant to mark the end of a cycle of the Mesoamerican long count calendar which is alleged to be just about a 5125 years old cycle. Some people interpret the import of this date differently and say this date will mark the beginning of some changes and transformations.
In the sector of astronomy axial tilt is also known as obliquity. The axial tilt is generally accepted to be the angle between the rotational axis and the line vertical to the orbital plane of an object. Now Earth's axial tilt is 23.4. The orbital plane of Earth is commonly known as ecliptic plane and the there's a different name for Earth's axial tilt 'obliquity of the ecliptic'. This axis remains tilted in the same direction across the year.