Electronics is the study of flow and control of electrons. Thus the branch of electronics engineering is to study the behavior of an electron when they flow through various materials or devices like resistor, capacitor, semiconductor devices etc under different conditions of applied electric field. The device which controls the flow of electrons is called electronic devices.
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| Electronic Components |
History of Electronics:
1. Vacuum tube:
It is also called as electron tube or valve and it was first developed by John Ambrose Fleming in 1904. The vacuum tube is a tube in which gas is removed and thus vacuum is created. The basic working principle of vacuum tubes is thermionic emission. When you heat up a metal the thermal energy makes some electrons loose. The vacuum tube consisted of two electrodes a cathode and an anode placed on either side of the tube. When the cathode is heated up due to thermionic emission the electrons are loosened and while applying positive voltage to the anode, these negatively charged electrons (e-) are attracted towards anode. By creating vacuum that is by removing the gas the path is made clear for the electrons to move from cathode to anode. Thus current is created. It was bulky and used lot of electrical power and because of the heat produced it reduced the life of tube.
Uses:
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| Vacuum tubes |
Vacuum tubes was used in early computers as switch or amplifier.
2. Transistor :
Transistor was invented in 1947 by John Bardeen and Walter Brattain while working under William Shockley at Bell Labs and they were awarded Nobel prize. Transistor is a three terminal semiconductor device used to amplify or regulates current or voltage flow and acts as a switch or gate for electronic signals like faucet controls the flow of water. A voltage or current applied to one pair of transistor’s terminals controls the current through another pair of terminals and it can amplify the signal also. Mostly silicon and germanium is used for manufacturing. Transistors are smaller in size than vacuum tubes and consume less and generate almost no heat.
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| Transistors |
Uses:
The first application of transistor was in Radios in 1950's
3. Integrated circuits’s:
Integrated circuits is a set of electronic circuits on one small piece(chip) of semiconductor material normally silicon. Integrated circuits were first developed on September 12th 1958 by Jack Kilby at Texas instrument with five integrated components resistors, capacitors, distributed capacitors and transistors. An integrated circuit can hold transistors, resistors and capacitors . These integrated circuits can perform calculations and store data using either digital or analog technology.
Uses:
IC’s found numerous applications from cars (automotive controls), televisions, computers, microwaves, portable devices like laptops, MP3, play stations, cameras, cellular phones to ship equipments, aero planes, space craft’s.
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| Integrated Circuits |
Evolution of Integrated Circuit:
SSI- Small Scale Integration(Tens of transistors-1950s)
MSI- Medium Scale Integration ( Hundreds of transistors-1960s)
LSI-Large scale integration (Thousands of transistors-1970s)
VLSI- Very Large Scale integration(Tens of thousands of transistors-1980s)
4. Very Large Scale integration (VLSI) :
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| Very large scale integrated circuits |
VLSI began in the 1970s. Before the introduction of VLSI technology most ICs had a limited set of functions. VLSI involves packing more and more logic devices into smaller and smaller areas. In other words it’s the process of combining millions of components into a single chip.
Uses:
Used in digital camera, cellphones, computers , automated machines etc
The advantages of VLSI design are
*High speed,
*Low power
*Physically smaller
*Higher reliability
*More functionality.
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