6th week ( TRANSISTOR AND IC )

HYE3X :)

in the class on Thursday last week ,, we had learnt and do the practical for the elctronic component ....

TRANSISTOR AND INTEGRATED CIRCUIT .

Before we start our class,, En. Ahmad Redzuan showed to us a few videos about ROBOWARS.. It is quite interesting and something new in Malaysia. It is different from ROBOCORN and I think UTM student can introduce this types of robot to the Malaysia and maybe in the future ,, Malaysia can have their own "transformers" .. hehe

TRANSISTOR

Now ,, I want to discuss a little about transistor .A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be much more than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.

FUNCTIONS OF TRANSISTOR

The essential usefulness of a transistor comes from its ability to use a small signal applied between one pair of its terminals to control a much larger signal at another pair of terminals. This property is called gain. A transistor can control its output in proportion to the input signal; that is, it can act as an amplifier. Alternatively, the transistor can be used to turn current on or off in a circuit as an electrically controlled switch, where the amount of current is determined by other circuit elements.

1. Transistor as a switch .Transistors are commonly used as electronic switches, both for high-power applications such as switched-mode power supplies and for low-power applications such as logic gates
2. Transistor as an amplifier .The common-emitter amplifier is designed so that a small change in voltage in (Vin) changes the small current through the base of the transistor; the transistor's current amplification combined with the properties of the circuit mean that small swings in Vin produce large changes in Vout.Various configurations of single transistor amplifier are possible, with some providing current gain, some voltage gain, and some both.

these are the transistors that we used .

TYPES OF TRANSISTOR

There are two types of transistors, which have slight differences in how they are used in a circuit.

A bipolar transistor has terminals labeled base, collector, and emitter. A small current at the base terminal (that is, flowing from the base to the emitter) can control or switch a much larger current between the collector and emitter terminals.

For a field-effect transistor, the terminals are labeled gate, source, and drain, and a voltage at the gate can control a current between source and drain.

Bipolar junction transistor

Bipolar transistors are so named because they conduct by using both majority and minority carriers. The bipolar junction transistor (BJT), the first type of transistor to be mass-produced, is a combination of two junction diodes, and is formed of either a thin layer of p-type semiconductor sandwiched between two n-type semiconductors (an n-p-n transistor), or a thin layer of n-type semiconductor sandwiched between two p-type semiconductors (a p-n-p transistor). This construction produces two p-n junctions: a base–emitter junction and a base–collector junction, separated by a thin region of semiconductor known as the base region (two junction diodes wired together without sharing an intervening semiconducting region will not make a transistor).

4 different transistors.

Advantages of transistor

The key advantages that have allowed transistors to replace their vacuum tube predecessors in most applications are

1. Small size and minimal weight, allowing the development of miniaturized electronic devices.
2. Highly automated manufacturing processes, resulting in low per-unit cost.
3. Lower possible operating voltages, making transistors suitable for small, battery-powered applications.
4. No warm-up period for cathode heaters required after power application.
5. Lower power dissipation and generally greater energy efficiency.
6. Higher reliability and greater physical ruggedness.
7. Extremely long life. Some transistorized devices have been in service for more than 50 years.
8. Complementary devices available, facilitating the design of complementary-symmetry circuits, something not possible with vacuum tubes.
9. Insensitivity to mechanical shock and vibration, thus avoiding the problem of microphonics in audio applications.

WAY TO DETERMINE THE TYPE OF TRANSISTOR

We used three different ways to determine the type of transistor. By using data sheets , by using component analyser and using multimeter .

1. By using data sheets . We didnt do this because data sheets can be obtain from Internet and books. But ,, there is no Internet connection to the computer there .
2. By using component analyser . It is the easiest way to determine the type of transistor . Just connect all three terminal of component analyser to the three pins of transistors . It will tell the user type of that transistor ,, which pins is base ,, emitter ,, and collector . It also will tell user the value of current and voltage .
3. By using digital multimeter . We must use try and error method which is try all pins with positive and negative terminal of multimeter . We must use diodemeter .If the diodemeter give readings, so the terminal is true for those pins .

INTEGRATED CIRCUIT

An integrated circuit or monolithic integrated circuit (also referred to as IC, chip, ormicrochip) is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material. Additional materials are deposited and patterned to form interconnections between semiconductor devices.

Integrated circuits are used in virtually all electronic equipment today and have revolutionized the world of electronics. Computers, mobile phones, and other digital appliances are now inextricable parts of the structure of modern societies, made possible by the low cost of production of integrated circuits.

Most common are 4,6,8,14,16,18 or 20 pins dual in lines chips. IC's can be soldered directly into printed circuit boards, or may plug into sockets which have already been soldered into the board . When soldering , ensure that the IC is the correct way round and that no pins have been bent underneath the body . Whwn fitting new IC's it is often necessary to bend the pins in slightly, in order to fit in into the board .

Integrated circuits were made possible by experimental discoveries showing that semiconductor devices could perform the functions of vacuum tubes and by mid-20th-century technology advancements in semiconductor device fabrication. The integration of large numbers of tiny transistorsinto a small chip was an enormous improvement over the manual assembly of circuits using discreteelectronic components. The integrated circuit's mass production capability, reliability, and building-block approach to circuit design ensured the rapid adoption of standardized ICs in place of designs using discrete transistors.

ADVANTAGES OF INTEGRATED CIRCUIT

There are two main advantages of ICs over discrete circuits: cost and performance.

Cost is low because the chips, with all their components, are printed as a unit by photolithography rather than being constructed one transistor at a time. Furthermore, much less material is used to construct a packaged IC die than to construct a discrete circuit.

Performance is high because the components switch quickly and consume little power (compared to their discrete counterparts) as a result of the small size and close proximity of the components. As of 2006, typical chip areas range from a few square millimeters to around 350 mm2, with up to 1 million transistors per mm2.

WAY TO DETERMINE PINS OF IC

We conducted only one way to determine the pins of IC, which is to determine which pin is number 1 until last pin.

by using physical inspection

We can observe from the top body of IC. Usually ,, manufacturer make a sign to tell user that the pin nearer that sign is pin number 1 . The sign often mark by dot , screw-like , or half-hole .

Then, we count from pin number 1 and so on ,, column by column . But,, for the next column ,, start count after last number of previous column . :)

I hope that I can make a circuit like this :) INSYAALLAH :)

that's all :)

see in the next entry :)