E11 Lab #3
Grading
2008

The following points will be assessed for each part from the report.

1. Touch Screen
   1. For input circuit
      1. Output when input is +10V. (3 points)

         >> %Use superposition and consider one source at a time.
         >> 10*vdiv(rp(30.9,39.2),127)+2.5*vdiv(rp(127,39.2),(30.9))
         ans =    2.4282

      2. Output when input is -10V. (3 points)

         >> %Use superposition and consider one source at a time.
         >> -10*vdiv(rp(30.9,39.2),127)+2.5*vdiv(rp(127,39.2),(30.9))
         ans =    0.0329

      3. Thevenin resistance. (3 points)

         >> rp(rp(30.9,39.2),127)
         ans =   15.2099

      4. Compatible with 2.5 volt A/D? (3 points)  -- Yes
   2. Table 1 w/ explanation. (10 points)
   3. Table 2 w/ explanation. (10 points)
   4. For I/O box input circuitry:
      1. Thevenin circuit from left. (3 points)
         

         >> Vt=2.5*vdiv(39.2,30.9)
         Vt =    1.3980
         >> Rt=rp(30.9,39.2)+127
         Rt =  144.2793

      2. Voltage with 5V source and 10k pullup. (3 points)
         

         >> 5*vdiv(Rt,10)+Vt*vdiv(10,Rt)
         ans =    4.7665

      3. Touch screen voltage - unconnected to I/O box. (3 points)
         

         >> 5*vdiv(0.2,0.2)
         ans =    2.5000

      4. Touch screen voltage - connected to I/O box. (3 points)
         

         >> %Use superposition and consider one source at a time.
         >> 2.5*vdiv(rp(Rt,10),0.1)+5*vdiv(rp(Rt,0.1),10)+Vt*vdiv(rp(10,0.1),Rt)
         ans =    2.5240
         >> %Only about 1% error (2.542 vs 2.5).

   5. Well-documented from "Program 4" (20 points)
   6. Touch screen image (5 points).
   7. Extra credit
      1. No display when not touched. (2 points)
      2. Dots connected. (2 points)
      3. Data smoothed. (2 points)
2.  PCB
   1. Working PCB (5 points)
   2. Description of circuit behavior (5 points)

Total =     /85=   %

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