Basic Electricity - Senior Secondary 1

TERM: 1^ST TERM

WEEK SEVEN

Class: Senior Secondary School 1

Age: 15 years

Duration: 40 minutes of 5 periods each

Date:

Subject: BASIC ELECTRICITY

Topic: RESISTOR III

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

I.) Explain the meaning of resistor color codes

II.) Identify resistors color codes

III.) Solve problems on resistor color codes identification

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures,

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION	TEACHER’S ACTIVITY	STUDENT’S ACTIVITY
STEP 1 INTRODUCTION	The teacher explains the meaning of resistor color codes and identify the color codes	Students listens attentively to the teacher
STEP 2 EXPLANATION	Teacher solve questions on resistor color codes identification	Students exhibit attentiveness and active engagement
STEP 3 NOTE TAKING	The teacher writes a summarized note on the board	The students copy the note in their books

NOTE

RESISTOR III

Resistor color codes

Resistor color codes are a way of representing the value and tolerance of resistors using colored bands. Each color corresponds to a digit or multiplier, allowing you to determine the resistance value by reading the colors on the resistor.

Resistor color codes consist of several colored bands on the body of the resistor. The number of bands and their positions may vary depending on the resistor's precision and type. However, the most common configuration includes four bands

The first two bands represent the significant digits of the resistor value.
The third band represents the multiplier, indicating the power of ten by which to multiply the significant digits.
The fourth band represents the tolerance, indicating the range within which the actual resistance of the resistor is expected to fall.

The colors are typically mapped to numbers as follows:

- Black: 0

- Brown: 1

- Red: 2

- Orange: 3

- Yellow: 4

- Green: 5

- Blue: 6

- Violet: 7

- Gray: 8

- White: 9

For instance, a resistor with bands of brown, black, red, and gold represents a resistance value of 10 x 10² ohms, with a tolerance of +/- 5%. So its resistance value is 1000 ohms (1 kiloohm) with a tolerance of +/- 5%.

Example 1: A resistor is coded as Grey, Red, Gold, Gold. Convert this color code.

8.2Ù, 5%

Solution

Color codes

Grey: 8 (first significant digit)

Red: 2 (second significant digit)

Gold: Multiply by 10^(-1) (or divide by 10), which means multiply by 0.1

Gold: Tolerance of +/- 5%

Combining these, we get: (8 * 10 + 2) * 0.1 = 82 ohms with a tolerance of +/- 5%. So the value of the resistor is 82 ohms with a tolerance of +/- 5%.

Example 2: How do you interpret the tolerance of a resistor from its color code?

Solution

The tolerance of a resistor is interpreted from the color of the fourth band. For example, gold represents ±5%, silver represents ±10%, and no band indicates ±20% tolerance.

Example 3: What resistance will cause a current of 250ùA, if the electromotive force is 18V.

Solution

R = Vt / I

= 18V/250ùA

= 72000 ohm = 72kilo ohm's

EVALUATION: 1. What is resistor color codes

What is the resistance value of a resistor with the color bands Red, Green, Brown, Gold?
Determine the resistance value and tolerance of a resistor with the color bands Yellow, Purple, Orange, Silver.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively

Basic Electricity - Senior Secondary 1 - Resistor III