f-stop = Focal Length / Aperture Size
Aperture Size = Focal Length / f-stop
diagonal = sqrt(a^2 + b^2)
Lens Equation
1 / Focal Length = (1 / Distance to Image) + (1 / Distance to Object)
where
Focal Length is lens focal length
Distance to Image is distance from lens to 'film' (ie screen)
Distance to Object is distanct from lens to LCD
Speaker Impedance
Speakers In Series: Rt = R1 + R2 +..
Speakers In Parallel: 1/Rt = 1/R1 + 1/R2 +..
Where Rt is Total Impedance
