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Basics of Electric Circuits

Resistive Touchscreen Voltage Mapping

Description

A resistive touchscreen uses voltage mapping to locate a finger touch on a mobile device. It is built from two metallic layers. The top layer is flexible, and the bottom layer is rigid. A narrow gap separates them, and the high resistance between the layers is an important part of the design.

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Transcript

一名设备工程师需要为移动设备设计电阻式触摸屏界面。该界面由两层导电层组成:一层柔性的上层和一层刚性的下层,两者之间由一个狭窄的间隙隔开。

两层之间的电阻较高。当触摸屏幕时,两层在称为触点的位置发生接触,从而降低层间的电阻。

为了确定精确的触碰位置,触摸屏被简化为一维系统。

顶层以其长度、电阻率和横截面积为特征,并在接触点处被分为两部分,其电阻与各自长度成正比。

如果在顶层的两端之间连接一个电压源,则该电路类似于一个分压电路,触点处的电压降取决于这两个电阻。

代入电阻值并求解方程,可得到触点处电压降与其位置之间的关系。

每个接触点的电压均不相同,这有助于精确定位位置。

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