We were asked to design digital voltage and current meter with 3 ranges(adsbygoogle = window.adsbygoogle || []).push({});

(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!

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Voltmeter design

**Physics Forums | Science Articles, Homework Help, Discussion**