Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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)
    V2=Vin.(R3+R4)/(R1+R2+R3+R4)
    V3=Vin.(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:
    R4=R3=30Kohm
    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
    attachment

    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)
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook