80 smart board.The principle of the resistive film technology is that the basic structure of the electronic whiteboard is composed of a multilayer film, including a horizontal wire resistive film, an insulating mesh, a conductive film, an insulating mesh, a vertical resistive film, etc., and the combined film has the same size as the used area. The working principle is to add a fixed voltage to the resistive film. Under the action of no external force, the conductive film does not contact the resistive film, no voltage is measured, and there is no information reaction of the positioning. When a hard object is pressed at a certain point of the resistive film, the current is read by the test circuit through the conductive film, just like a point test from a potentiometer to a varying voltage, which is related to the position of the touch point, according to the level The voltage read in the vertical direction can be converted to the X, Y direction position of the touch point. The resistive touch screen is a grid scanning implementation, which is characterized by the fact that when an object is pressed against the surface of the film, it can reflect the position where the object is pressed.