Consider we want to build a touch screen. We start by creating two layers. The t

Question

Consider we want to build a touch screen. We start by creating two layers. The top layer is held at a constant voltage V = 3 Volts and the bottom layer being made of an array of resistors connected in series. The bottom layer is connected to an ammeter and if we touch the screen at a point we will connect the circuit. (See Figure 1) Based on the reading of the ammeter we can determine where the screen was touched. Consider two dimensions such that one set up exists for x and one for y. We have two ammeters which read Ix = 1 mA and Iy = 0:428 mA. If R = 100 for each resistor and they all have a length LR = 1 mm then which (x; y) point am I pressing on the screen?

Explanation / Answer

V/Ix=Rx=3000 ohm

so number of resistors in between=3000/100=30

so x coordinate=30

V/Iy=3000/0.428=7000 ohms

so number of resistors in between=7000/100=70

soy coordinate=70

poiunt of pressing=(30mm, 70mm)

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.