overhead projector

Thân thiện

The teacher places a transparency on the overhead projector.

Definition

Noun: A device that projects an enlarged image of a transparent sheet (an overhead transparency) onto a screen or wall. It consists of a bright lamp, a fan for cooling, and a stage where the transparency is placed. The light passes through the transparency and a lens system projects the image over the head of the operator.

Usage

The term "overhead projector" refers specifically to the projection device itself. It is a compound noun. * The teacher used an overhead projector to show the diagram to the entire class. * Before the digital age, business presentations often relied on overhead projectors and transparencies.

Examples

• "She placed the acetate sheet on the glass stage of the overhead projector."
• "The bulb in the overhead projector burned out during the lecture."
• "This meeting room is equipped with a screen and an overhead projector."

Advanced Usage

• The device is often abbreviated as OHP in informal or technical contexts.
  • Do you have an OHP available for the workshop?
• The transparent sheets used with it are called overhead transparencies or simply overheads.

Variants and Related Words

• Projector (n): A more general term for any device that projects an image or film onto a surface.
• Digital Projector (n): A modern projector that connects to a computer to display digital images, largely replacing the overhead projector.
• Slide Projector (n): A projector used for displaying photographic slides.

Synonyms

• OHP (abbreviation)
• Viewgraph projector (less common)

Notes

• "Overhead projector" is a fixed compound noun. It is not typically used as a phrasal verb or in idiomatic expressions.
• The term describes the path of the projected light ("over the head" of the user) and should not be confused with general business "overheads," which refer to ongoing operating expenses.

Học thuật

Noun

1. a projector operated by a speaker; projects the image over the speaker's head