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Homework Help: Voltmeter design

  1. Dec 26, 2005 #1
    We were asked to design digital voltage and current meter with 3 ranges
    (20 100 200) v for voltages and two ranges
    (2, 20)A for amperes
    Note: supply voltage is 5V
    maximum value for resistors of ampere meter must not exceeded 0.5 ohm

    V1=Vin. (R2+R3+R4)/(R1+R2+R3+R4)

    Where V1=V2=V3=V4=1 V
    Vin changes respectively with V1,V2,V3 as 20,100,200
    So we used those equations mentioned above when we considered R1+R2+R3+R4=6000 Kohm but we get these values:
    R2= -30
    Note: we have no problem with current meter,that's why I haven't referred to it at the attachment
    Need help!
    Thanks in advance!
  2. jcsd
  3. Dec 26, 2005 #2

    sorry, i can't download the my schematic cause it exceedes the max.file size

    i don't know may be try later
  4. Dec 26, 2005 #3
    What type of file are you trying to attach?
  5. Dec 26, 2005 #4
    PNG file , but it's oversize (about 400KB)
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