NEC lt80 Installation Guide

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Notes and Formulas                                                                       Page 1

Projection Distances and Screen Sizes

Ceiling Mount                                                                   Page 2

Desktop Setup                                                                  Page 3

Cabinet Dimensions                                                                       Page 4

Ceiling Mount Dimensions                                                              Page 5

§ For Screen Sizes of 24 to 300 inches not indicated on the projection tables, use the formulas below.

§ Set the projection distance based on the width of the screen.

§ If the figures on the tables do not match the figures in the formulas, use the figures in the table.

§ All dimensions are in inches. Multiply by 25.4 for millimeters.

§ Distances may vary +/- 5%.

A = C / COS 

α

B = ((H x 1.25) – 0.2) x 3 / 25.4

C (WIDE) = ((H x 12.5 / 243) – 0.06) x 39.37

C (TELE) = ((H x 12.5 / 187) – 0.06) x 39.37

αα 

= TAN 

-1

 ((H x 0.375) + B) / C

H = Width of screen

A = Distance between lens center and screen center

B = Vertical distance between lens center and screen bottom (screen top for ceiling mount)

C = Horizontal throw distance between screen surface and projector lens

αα 

= Offset Angle of image path center line with reference to desktop or ceiling