Basic voltmeter with 7-segment display using A/D converter

[Kaleen]

Hi, I started designing and simulating my project :idea: , consisting in a basic voltmeter made with op-amps connected to an A/D converter whose outputs are connected to a 74LS47 Decoder and this to a 7-segments display (does anyone get confused :? ?? see the image attached :wink: )...
but....the simulation in workbench doesn't work, really i don't know how to connect the A/D converter and i don't know if i have something else wrong connected or missing or what's happening ...could anybody help me with this :?: :?:... :cry: ...

 

[crust]

Without going through your whole circuit, there is one thing I do not understand and one that I think is wrong. I dont understand what that big box with the -5 from the inverting input to ground is for.

On the output of the ADC, it seems that you are only using the bottom 4 bits of the ADC. It is an 8bit devices so your voltage steps are going to be between 5/(2^8) = 20mV (about). That means you can read up to 140mv and then you get 0. It seems what you have is a system that shows the Voltage modulo 160mV. I doubt this is what you are after.