DC volts and A/D converter

[mnm43]

DC volts and A/D converter

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I'am using a 16F877A for my project...and I need to get the DC voltage from and other circuit (0 to 100 volt dc). This voltage is use for my calculation and results are shown on display.

I have found schematic for voltage 0 to 5 volts. The idea is to bring the 0 to 100 volt to scale 0 to 5 ( only one scale, no pot or resistors with selector).

A schematic that i have found is
**broken link removed**

But i don' t need the display. I need to get voltage the same way but instead of the ilc7107 it would be with my 16f877a.

Can anyone help me with this.

Tanks

 

[Nigel Goodwin]

Simply a resistive attenuator (potential divider), two resistors is all you need, bearing in mind the source impedance the 16F877 needs to see.

Check my PIC tutorial which does just that, but for 0-10.23V with a 2.5V reference (so divide roughly by four) - you would only need to change the value of the input resistor to give a 100V range (preferably actually 102.3V range).

 

[mnm43]

Tanks Nigel!