What is ohp?

An Overhead Projector (OHP) is a device used to project transparent sheets onto a screen or wall. It was commonly used in education and presentations before the widespread adoption of digital projectors.

Key aspects of OHPs include:

• Transparency Films: The OHP uses transparent plastic sheets, known as <a href="https://www.wikiwhat.page/kavramlar/transparency%20films">transparency films</a>, on which text or images are drawn or printed.
• Light Source: A bright <a href="https://www.wikiwhat.page/kavramlar/light%20source">light source</a> shines through the transparency.
• Lens System: A lens system focuses and projects the enlarged image onto the screen. A <a href="https://www.wikiwhat.page/kavramlar/Fresnel%20lens">Fresnel lens</a> is frequently used.
• Simple Operation: OHPs are relatively simple to operate and require minimal setup.
• Interactive Use: Presenters can write or draw on the transparency during the presentation, making it interactive.
• Declining Use: OHPs have largely been replaced by digital projectors and interactive whiteboards due to their limitations in terms of color, dynamic content, and the need for physical transparencies. However, they remain useful in situations where simplicity and immediate annotation are prioritized.