👉 A slide meter or slide scale is a type of instrument used to measure small changes in position, direction, or speed. It consists of an optical device that displays a line of zero or one on a screen, and a reference point that is located at the center of the slide. The slide moves along the axis of the slide meter, and as it moves, the line of zero or one on the display will move accordingly. The term "slidometer" refers to this type of instrument,