Hi Laura,

You can use two 10 K resistors to make a voltage divider.

                           Ain
Vin--------R1----------+------------R2--------------Gnd

Vin - 0-10 volts in (voltage to be measured)
Ain - connect to ADC input
R1 - 10K
R2 - 10K
Gnd - Ground

Formula to calculate the divider is

Vout = Vin (R2/(R1+R2))
Vout = 10(10K/20K)
Vout = 10*0.5
Vout = 5v

So when your Vin is 10V your Vout will be 5V (full scale if you use 5V
reference).

Hope this helps.

-- 
Chetan Bhargava
Web: http://www.bhargavaz.net
Blog: http://microz.blogspot.com


On 5/1/05, laura capaldi <lauracapaldi01@yahoo.com> wrote:
> Hi,
> 
> I'm planing to use the A2D functionality of the 12F675 to convert 0-10V out to a 0-1024 range, 10 bit A2D conversion. Everything on the 12F675 looks good for that. My question is whether I have to supply a 10V for Vref/GP1/AN1 or is there a way to scale VDD internally such that I can get a 0-10V mapping on the A2D conversion that is performed on AN0?
> 
> Thanks,
> Laura

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