What are the principles involved in using overhead projector?

The principles of using an overhead projector include the transmission of light through transparent materials and the projection of enlarged images onto a screen. The projector uses a bright light source to illuminate the transparencies placed on the glass surface, allowing the image to be magnified and displayed. Proper alignment and focus are crucial for clarity, while the choice of transparency materials impacts the visibility and quality of the projected image. Additionally, effective use involves considering audience sightlines and ambient lighting conditions to enhance visibility.