TYPES AND CHARACTERISTICS OF OHP(OVERHEAD PROJECTOR)

PISMP TESL 3 SEMESTER 4

Prepared by, Nur Inani bt Hasim

CONTENT

ITEMS SLIDE NUMBER

Definition 3

Parts of Overhead Projector 4

Examples of Overhead Projector

a) Transmissive Overhead Projector

b) Reflective Overhead Projectorc) Opaque Overhead Projector

567

Features to Choose 8

Types of Transparencies 9

Techniques for the Preparation and

Presentation Transparencies

10, 11, 12, 13,

Transparency Preparation Principles

14, 15

Advantages of OHP 16

Disadvantages of OHP 17

DEFINITION

OVERHEAD PROJECTOR (OHP)

A device that projects an enlarged image of a

transparency placed on it onto a wall or screen by means of an

overhead mirror.

Lets label!

TRANSMISSIVE OVERHEAD PROJECTOR

REFLECTIVE OVERHEAD PROJECTOR

OPAQUE OVERHEAD PROJECTOR

3 FEATURES TO CHOOSE

Lens Type

• Image quality increases as you progress from the basic singlet lens type, to the advanced triplet lens type

Brightness (Lumens)

• 2000 – 2500 lumens (depends)

Lamp life

• Determined by the rating in lumens and lamp type• Generally lasts less than 100 hours• ENX offers the longest lamp lasting period

TYPES OF TRANSPARENCIES

Write-on Thermal (infra-red) Photocopying Ink-jet Film

P/S : Transparency is the medium that is similar to a slide which is classified as teaching aids in the form of projection view.

TECHNIQUES FOR THE PREPARATION AND PRESENTATION TRANSPARENCIES

1. Write-on technique

drawn together by hand or machine directly on transparency film

broadcasted directly to the audience.

 

2. Window technique several windows that

cover certain parts of the surface of transparencies

When used, the windows will be opened one by one like the home window to display the contents or images.

3. Striped techniques This techniques

have bands either horizontally or vertically

It’s opened only one way not as open windows technique in both directions. Only 3 to 4 strips in a transparency.

4. Overlapping techniques (layered)

Consists of films that are placed directly on the basis of a fixed frame

Some additional film placed on the sides of the frame.

5. Round technique It seeks disclosure of

or part by part to reveal anything needed

It can be made in the cover inserts (vertical, horizontal or diagonal or rounded cap. Spherical cap can be made by means of a pinned in the middle.

6. Animation techniques It uses plastic sheets

polarising fixed upon certain parts of the image that is on the transparencies

during usage, the device is placed on the lens polariser OHP bay. The image will appear to move when the image is pulled or moved.

Overlapping technique

Window technique

TRANSPARENCY PREPARATION PRINCIPLES

Plan appropriate methods or techniques before starting to make transparency with existing equipment.

Analysis of the information to be communicated carefully in terms of use, objectives and content.

Determine the presentation format. Longitudinal or vertical format. Avoid obscure format

Make sure each creation (graphics, statements) are within 2 cm from the edge of the transparent material.

Clarity of alphabets depending on the type, size, spacing between letters and spacing between rows.

The smallest image on the screen should be 2:56 cm in height for every 8 meters distance display.

Use a larger font for headings and sub-headings.

Restrict writing between 6 and 7 lines in a piece of transparency.

Use 7 to 10 words on every sentence.

Advantages of Overhead Projector

Audience reach

User friendlySequence of

materials

Disadvantages of Overhead Projector

Resolution

Problems

Cost to Replace Bulbs

Transportation

Displaying

Material

Outdated Technolo

gy