how to use pic for measuring voltage

[emeleen08]

hi,
i need to make a project for monitor supply voltage(240vac)
but i dont know make connection between voltage supply-ADC-pic.
pleasee help me?

[sich]

Hi emeleen08,

I've never try it before but I guess using a transformer to convert the AC240V to a voltage less than your microcontroller's ADC input limit (let say 4V) will do. Then, rectify the AC to DC and connect it to PIC's ADC pin.

The converted and rectified voltage must be lower than the ADC's voltage limit so that it won't spoil the chip when the AC supply is not stable and sometimes higher than AC240V. A voltage clamp circuit (zener diode and resistor) to protect the ADC pin from voltage higher than its limit maybe needed for additional protection.

Since this involves high voltage, please be careful and take all precautions while working on it

[shahrul]

using a transformer to convert the AC240V to a voltage less than your microcontroller's ADC input limit (let say 4V) will do. Then, rectify the AC to DC and connect it to PIC's ADC pin.

Yes, that will be working.
Other option, you can use Voltage Transducer and ofcourse you still need to rectifies the output from transducer.