CHAPTER II

BASIC ELECTRONIC COMPONENTS

A. BASIC COMPETENCE/INDICATORS

After completing this course, you will be able to:

1. Identify passive component and explain each of the component

2. To differentiate between fixed resistors and variable resistors.

3. Calculate the resistance of resistor

4. Identify and analyse the type of capacitor

5. Identify active component and explain each of the component.

6. Identify and analyse the type of diode and transistor

7. Explain the contribution and application of active component.

B. MATERIALS

There are several basic electronic components that we can find around us, mainly:

1. Passive Components

- Resistors

- Capacitors

- Inductors

- Diodes

- Interface components

2. Active Components

- Transistors

Bipolar

Field effect

- Integrated circuits

Analog

Digital

Microcontroller

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Fig. 2-1 Basic electronic components

2.1 Resistors

The function of resistor is to resists or slows down the flow of electrons.

The two main characteristics of a resistor are its resistance, R, in ohms and

its power rating, P, in Watts.

The resistance, R, provides the required reduction in current or the desired

drop in voltage.

The wattage rating indicates the amount of power the resistor can safely

dissipate as heat. The wattage rating is always more than the actual

amount of power dissipated by the resistor, as a safety factor.

Generally, there are two category of resistor, namely:

a. Fixed Resistors

• Can only handle a certain amount of current.

• Typically made from a resistance wire, which is “wound around a ceramic core

and covered with some insulating material”.

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Fig. 2-2 Example of fixed resistor

b. Variable resistors

• Also known as rheostats, or potentiometers

• Allow you to regulate the amount of current flowing through the circuit

• Resistors are non-polarized, which means there are no positive or negative ends

Fig. 2-3 Potentiometer

A. Types of Resistors

Wire-wound resistors

Carbon-composition resistors

Film-type resistors

Carbon film

Metal film

Surface-mount resistors (chip resistors)

Fusible resistors

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Thermistors

Wire Wound Resistor

Special resistance wire is wrapped around an insulating core, typically

porcelain, cement, or pressed paper.

These resistors are typically used for high-current applications with low

resistance and appreciable power.

Fig. 2-4 Wire Wound Resistor

Large wire-wound resistors with 50-W power ratings. (a) Fixed R, length of 5 in. (b)

Variable R, diameter of 3 in.

Carbon Composition Resistors

Made of carbon or graphite mixed with a powdered insulating material.

Metal caps with tinned copper wire (called axial leads) are joined to the

ends of the carbon resistance element. They are used for soldering the

connections into a circuit.

Becoming obsolete because of the development of carbon-film resistors.

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Fig. 2-5 Carbon resistors with the same physical size but different resistance values.

2.2 Capacitors

• Basic job is to store electron current until needed by the circuit

• Charge and discharge electrons as required by the circuit

• Made up of two or more plates (conductors), each separated by a dielectric

(insulator)

• Ceramic capacitors and mica capacitors are non-polarized

• Electrolytic capacitors are polarized, meaning one lead is positive and the other is

negative, as marked

• Values specified in microfarads (μF) or picofarads (pF)

• Marked with actual value or a numeric code

• Some varieties are +/- polarized

Fig. 2-6 Capacitors2.3 Inductors

Values specified in henries (H), millihenries (mH) and microhenries (μH)

A coil of wire that may be wound on a core of air or other non-magnetic material, or on a

magnetic core such as iron powder or ferrite.

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Tantalum

Ceramic Electrolytic Mica Tantalum

The symbols of inductors are or

Two coils magnetically coupled form a transformer.

Inductor types:

Fig. 2-7 Inductors

2.4 Diodes

• A solid state device designed to permit the flow of electrons in one direction and

block the flow in the opposite direction

• Most modern diodes are semiconductor devices, but are considered passive since

they do not contribute any amplification or gain to a circuit.

• Made from germanium or silicon

• A zener diode is used to regulate voltage

• A light emitting diode (LED) is a solid state component that emits a tiny bit of

light when current passes through it

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Fig. 2-8 Diodes symbols

Diode types

May be classified by semiconductor material (silicon, germanium, gallium arsenide, etc)

or classified by circuit function.

Fig. 2-9 Diode types

2.5 Interface components

Interface components are consisted of :

- Switches

- Plugs

- Sockets

- Panel controls

a. Switches

Switches is a device which closes to complete an electrical circuit allowing electrons

to flow through the circuit, or which opens or breaks a circuit, stopping the flow.

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Fig. 2-10 Switches

b. Plug

Two common plug styles:

Fig. 2-11 Plugs

2.6 Transistors

• The symbols of transistor are as follow:

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• Solid-state device used for switching and/or amplifying the flow of electrons in a

circuit

• Two basic types of transistors are switching and amplifying

• Switching transistors are used in circuits, which are either on or off

• Amplifying transistors amply an electrical signal are used in places where the

amount of signal is important

• A phototransistor is a solid state component where the amount of light which

passes through a lens controls the amount of current flow

Fig. 2-12 Transistors

2.7 Integrated Circuits

• Three common electronic components, which make up an integrated circuit, are

resistors, transistors and capacitors. The main advantage of ICs is that so much

electronic circuitry can be in such a small package.

• Integrated circuits (ICs) are multi-terminal devices that provide an array of

functions and applications far to numerous to list here.

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Fig. 2-13 Integrated Circuit

Pin identification and numbering convention

- Pins are numbered sequentially in a counterclockwise direction.

- Pin 1 is often identified with a dot or a dimple.

- The pin 1 end of the chip is often identified with a notch.

Fig. 2-14 Pin identification and numbering convention

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