Real Engineering Science Essay Sample
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Real Engineering Science Essay Sample
The 20th century was a period of revolutionary discoveries and developments, home to the foundations of all the technology we know and use today and without it the world would be a completely different place. Throughout the 20th century there was innovation and invention happening around every corner, but the major area of invention was the development of communication technology. The radio became a huge appliance in the early 1900s and played a significant role in both World War I and World War II, however like a range of other appliances, the radio used a vacuum tube.
Vacuum tubes were used for processing binary code sent via radio wave to decipher what the message said, this principle was also applied to televisions and sound recording devices. The vacuum tube was a glass tube that contained 3 parts to it, an anode, grid and a cathode. When a charge was run through the cathode it would give off electrons, then due to the tube being vacuumed there was no resistance against the electrons and this allowed for them to move on to reach the anode.
The grid sat between the anode and cathode and ran a charge through it that control the flow of electrons to the anode from the cathode. A simple example of this can be seen in a light bulb where the vacuum tube acts as a switch and if the grid is positively charged the electrons will go through to the anode and the light will illuminate, however if the grid was subjected to a negative charge then the electrons would bounce back and the light will stay off, this is clearly demonstrated in a video by Real Engineering.
This same principle was applied to receiving data from a radio wave and the binary could be decoded and signals would be interpreted. However the vacuum tubes required lots of power to work and they needed time to heat up before they would work, this meant they would burn out easily and require replacement and on top of all that they were big and bulky but the vacuum tube was replaced in 1947 by a semiconductor known as a transistor.
A semi conductor works similarly to vacuum tube however it works using variable electro conductivity. The semiconductor uses a crystal lattice of silicon all made up of valence 4 atoms, the current flow is altered by the addition of impurities into this lattice such as phosphorus atoms with a 5th electron, by adding the extra electron it travels around the lattice this is called an N-type. When placing a boron atom into the lattice with only 3 electrons it creates hole for the electrons to jump into and current flows through the lattice, this is known as P-type.
When a transistor is made of N-P-N terminals the holes from the P-type are filled with the N-type and thus forms the depletion layer which restricts the flow of electrons similar to the grid in the vacuum, but if a positive charge is applied to the base(P-type terminal) the electrons flow through and the circuit is complete, this is again demonstrated in the video by Real Engineering. All this means that a transistor can act the same way as a vacuum tube without the issue of overheating or the need to heat up before it worked, the transistor soon dominated the industry and quickly replaced the vacuum tube. The transistor may have been a little bulky to begin with but it was still smaller than the vacuum tube and it was better in every way.
As each year passes the development if the transistor improves and the circuits are made smaller and smaller as the technology gets better and better. The development of the transistor meant radios could be made smaller and portable, along with TVs and other appliances. The transistor re shaped the modern world and changed the way things are today with transistors being used in every kind of electric appliance and it most certainly revolutionised the world of communication in the 20th century.