module 3 with answers - quia – electrical workshop module 3: basic electrical components 3 3.1...

Electrical Workshop

Module 3: Basic Electrical Components

PREPARED BY

Academic Services Unit

August 2012

© Applied technology High Schools, 2012

ATE210 – Electrical Workshop

Module 3: Basic Electrical Components 2

Module 3: Basic Electrical Components

Module Objectives

Upon successful completion of this module, students should be able to:

1. Identify basic electrical components such as:

Lamps, motors and buzzers.

Resistors, LDRs, capacitors and inductors.

Diodes.

2. State the application of each component.

Module Contents:

Topic Page No.

3.1 Introduction 3

3.2 Basic Electrical Components 3

3.3 Components Coding 6

3.4 Class and Lab Activities 9

3.5 Review Exercise 14



3.1 Introduction Have you ever opened your personal computer (PC) or your radio from the inside? If

you tried so, have you seen the electrical boards with many components mounted on

them? Figure 3.1 shows an example of a PC electrical board with different

components. In this module, we will study these components and understand their

usages and applications.

Figure 3.1: PC Electrical Board

3.2 Basic Electrical Components

Component Symbol Function Picture

Lamp

Light Indicator

Motor

Motion Indicator

Buzzer

Sound Indictor




Resistor

Resistors limit the current flow

Variable Resistor

Variable resistors control the current in the circuit:

- Adjust lamp brightness - Adjust motor speed

They are also called potentiometers

LDR (Light Dependent Resistor)

LDRs are variable resistors where resistance value changes with light




Capacitor

Capacitors store electrical charge and are used in:

- Timer Circuits

Inductor

Inductors store magnetic field and are used in:

- Electric bells - Door locks

Diode

Diodes allow current to flow in one direction only. Diode has two terminals:

1. Cathode (K)(-) : located to the line perpendicular to the point of the arrowhead

2. Anode (A) (+): located at the opposite end of the cathode.



3.3 Components Coding: 1. Resistance Coding: Resistors are specified by their resistance value and their

tolerance. One way to indicate the resistance value and tolerance is color code method, which is explained in Figure 3.2.

1. Resistance is measured in ohms (Ω) 2. Most resistors have 3 bands:

• The 1st band gives the first digit. • The 2nd band gives the second digit. • The 3rd band indicates the number of zeros. • The 4th band gives the tolerance

Figure 3.2 Resistance color code



• Exercises: State the resistor’s value and tolerance for the following resistors:

R = 470 Ω ± 10%

Yellow Violet Brown Silver

4 7 0 ±10 %

R = 25 Ω ± 5%

Red Green Black Gold

2 5 ±5 %

R = 72 Ω ± 5%

Violet Red Black Gold

7 2 ±5 %

R = 94000 Ω ± 10%

White Yellow Orange Silver

9 4 000 ±10%

R = 25000 Ω ± 10%

Red Green Orange Silver

2 5 000 ±10%

R = 65000 Ω ±5%

Blue Green Orange Gold

6 5 000 ±5 %



2. Capacitor Coding: Capacitors are usually specified by three quantities;

capacitor value, tolerance and voltage rating. A number code is often used

on small capacitors where printing is difficult.

• The 1st number is the 1st digit,

• The 2nd number is the 2nd digit

• The 3rd number is the number of zeros to give the capacitance in pF

• Ignore any letters - they just indicate tolerance and voltage rating.

• Example 1: You have a capacitor with "104" stamped on it.

- The first two digits are: 1 0

- The third digit is: 4 so add four zeros to the 1 0 à 1 0, 0 0 0 0 pF

• Exercises:

State the capacitance value for the following capacitors:

C = 1000 pF C=68000 pF C = 2200 pF

C = 150000pF C = 470pF C = 540pF

102 683 222

154 471 541



3.4 Class and Lab Activities:

Activity 1: Identify resistance value for the resistors provided by your instructor.

§ Items Required:

Resistors with various values

§ Steps:

1. Using the color coding method, identify the resistance value of various

resistors

2. Fill the table below:

No 1st band color and

value

2nd band color and

value

3rd band color and

value

Resistance (Ω)

Tolerance

1 Blue Black Red 6000 5%

2 White Blue Green 9600000 10%

3 Black Brown Red 1000 5%

4 Brown Brown Red 11000 10%



Activity 2:

Light intensity control using potentiometer (variable resistor).

§ Items Required:

Potentiometer 9V Battery 9 V Light Bulb Alligator Clips

§ Steps:

Connect the following circuit:

Rotate the spindle of the potentiometer. What do you observe on the light

brightness?

The light will increase or decrease depending on the direction of the movement.

State an application of potentiometers

Light dimmers, speed control (fan), sound control (speakers).



Activity 3: Demonstrate LDR Operations

§ Items Required:

LDR 9V Battery 9 V Light Bulb Alligator Clips

§ Steps:

1. Connect the following circuit:

2. Expose the LDR to light. What happen to the brightness of the lamp? When the LDR is exposed to light, the resistance decreases and the current increases, so the lamp will be brighter.

3. Put the LDR in the dark. What happen to the brightness of the lamp?

When the LDR is exposed to dark, the resistance increases and the current decreases, so the lamp will be dim.

4. State some applications of LDRs. Mobile phones



Activity 4: Identify capacitance for the capacitors provided by your instructor.

§ Items Required:

Capacitors with various values

§ Steps:

1. Identify the capacitance value of various capacitors.

2. Fill the table below:

No Number displayed on the capacitor Capacitance (F)

1 333 33000pF

2 380 38pF

3 147 140000000pF

4 236 23000000pF

3. State some applications of capacitors.

Timer Cicuirts

Toy cars



Activity 5: Draw the symbols for the following components:

Components Symbol

LDR

Diode

Variable Resistor

Capacitor

Resistor

Inductor



3.5 Review Exercise: To complete this table see Module 3.4 and5

Exercise 1: Complete the following table Component Symbol Function

Lamp

Sound Indicator

Capacitor

Non-polarized symbol:

Capacitor

Polarized symbol:

Used to control the flow of the current

LDR



Exercise 2:

• If the value of a capacitor is 1000 pf, what is the capacitor code that should be stamped on it? 103

• The value of the capacitor shown below is: 1540000pF

Exercise 3:

Draw the electrical symbol of the diode and mark the anode and cathode:



Exercise 4:

Complete the following:

• LDR stands for: Light dependent resistor

• When the LDR is exposed to light it has a low resistance.

• When the LDR is exposed to darkness it has a high resistance.

• An electrical component allows the current to flow in one direction only: diode

• An electrical component that stores magnetic field: inductor

• An electrical component that stores electrical charge: capacitor

• An electrical component that is used to adjust the lamp brightness: Variable Resistor

• An electrical component that is used to adjust the motor speed is Variable Resistor

•

• An electrical component that is used to limit the flow of current is: resistor

module 3 with answers - quia – electrical workshop module 3: basic electrical components 3 3.1...

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