INTERACTIVE LEARNING MODULE

INTERACTIVE LEARNING MODULE

TRANSISTOR

BY : SITI NADIA BT ADNAN

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CONTENTS

LEARNING STANDARDS

OBJECTIVES MODULE

TRANSISTOR

VIDEOS

Exercises and Quizzes

LEARNING STANDARDS

Students can :

• Describe the function and use of transistors as current amplifiers

• Describes a circuit containing a transistor as an automatic switch

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OBJECTIVES MODULE

• Able to strengthen students' mastery and skills regarding the transistor subtopics presented through this module.

• Trainee teachers can carry out learning and teaching activities in a planned and systematic manner.

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TRANSISTOR

• Introduction of transistor

• The way a transistor is connected in a circuit

• Transistor principle

• Transistor as a current amplifier

• Transisor as automatic switch

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INTRODUCTION OF TRANSISTOR

A transistor is an electronic device made from the fusion of a thin layer of semiconductor. Transistors consist of three layers of a semiconductor material, each capable of carrying a current..

A transistor is used to amplify or switch electronic signals and electrical power. Transistor also can amplify a signal.

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TYPES OF TRANSISTOR

There are two types of transistors, namely: (a) Transistor npn (b) Transistor pnp

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• A transistor has three terminals namely:

(a) Base (b) Collector (c) Emitter

• The arrow on the transistor symbol indicates the direction of the current flow allowed to flow.

Transmitter terminal, E

• Supplying charge carriers to the collector, C

Base terminal, B

• Control the flow of carriers charge from manufacturerto collector

Collector terminal, C

• Receive charge carrier from manufacturer, E

Transistor

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The Way a Transistor is Connected in a Circuit

•  Transistors should be connected to the battery terminals properly based on the type of transistor.
•  To connect the npn transistor, the positive terminal of the battery is connected to the collector, C and the negative terminal of the battery are connected to the manufacturer, E.
•  To connect the pnp transistor, the positive terminal of the battery is connected to the manufacturer, E and the negative terminal of the battery are connected to the collector, C.
•  To enable a transistor circuit to function, a p-n junction will biased forward, while another p-n junction will be biased inverted when a voltage is applied across the transistor.

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VS

1- See site terminal - if n - connect negatively - if p - connect positively 2- Termianal collector must be different from transmitter terminal - if transmitter terminal (-), collector terminal (+) - if the transmitter terminal (+), the collector terminal (-)

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TRANSISTOR PRINCIPLE

1) The base current, Ib is smaller than the collector current, Ic. Producer current, Ie is the sum of Ib + Ic Ib <Ic <Ie Ie = Ib+Ic 2) If Ib = 0, then Ic = 0 3) A small change in Ib will produce a large change to Ic

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TRANSISTOR PRINCIPLE

• The BE junction is lame forward. Electron as a majority charge carrier in semiconductors type - n flows from the manufacturer, E into site, B. • Due to the base layer, B is thin, then the majority of charge carriers are loopholes is limited. • Only a small fraction of electrons flow through the BE junction joining the hole at in semiconductor layer type - p. Number these tiny electrons flow out of the site, B as valence electrons. A site current, the Ib small results. • Most electrons from the manufacturer, E will attracted into the collector, C through the layers site, B thin due to potential difference in collector, C is more positive. • Electron flow into the collector, C produces a collector current, Ic.

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Transistor as a current amplifier

• A transistor acts as an amplifier by raising the strength of a weak signal.

• The low resistance in input circuit, lets any small change in input signal to result in an appreciable change in the output. The emitter current caused by the input signal contributes the collector current, which when flows through the load resistor RL, results in a large voltage drop across it. Thus a small input voltage results in a large output voltage, which shows that the transistor works as an amplifier.

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Transistor as a current amplifier

• When a sound reaches the microphone, the sound energy causes the diaphrag microphone vibrates and a variable current is generated. • Capacitor, C in the circuit blocks current directly from the battery but allows current fluctuating from the microphone through it. • The variable current then causes a change to the site current, Ib. • A small change in site current, Ib, causes a larger change in the collector current, Ic. • The variable collector current flows in the speakers and is converted to sound waves that have the same frequency as the original sound waves but with higher amplitude. • Thus, the output on the speakers is greater than the input on the microphone. • Multiplication of current by transistor = Ic/Ib

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Transistor as automatic switch

1. Works to turn on or off switches and electrical appliances such as lights2. Automatic control actions are generated using formula dividersV1= (R1/R1+R2)×VV2= (R2/R1+R2)×V3. If the resistor can be changed, R2 = 0, V2 = 0 and the transistor cannot be turned on 4. If R2 is raised, V2 will increase as well 5. When V2 reaches a certain minimum value, Ib will act to turn on the transistor 6. Collector current, a large Ic will flow and light the bulb

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1) Light sensitive resistors (PPC)

• PPC is a resistor whose resistance value changes in light intensity • In bright conditions, PPC resistance is low, then the voltage across the PPC decreases. This condition reduces site current, Ib. By This, the current collectors, Ic is also reduced and L lights are not can be turned on. • In the dark, PPC resistance is high, then the voltage across the PPC increases. This situation adds to the current of the site, Ib. By this, the collector current, Ic also increases and the lamp L in the collector circuit will be turned on.

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SELF-REFLECTION

• New things i have learnt in this transistor subtopics are ...................................................... • The most interesting things i have learnt in this subtopics is .................................................... • The things I still do not fully understand are .................................................... • I need to .................................................... to improve my performance in this subtopics

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VIDEOS ABOUT TRANSISTOR

• Video 1

• Video 2

• Video 3

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EXERCISES AND QUIZZES

• Exercises

• Answer scheme

• Quizzes

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THANKS!

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