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How to read adc AC voltage ?

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kichapi

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how to read adc AC voltage please help me?
 

btbass

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Re: adc AC volt

This depends on the type of reading you want to do?
The simplest way is to rectify the AC voltage and read the resulting DC level, this will give you peak AC volts.
You can get some IC's that convert AC voltages to RMS DC levels. Google 'rms to dc converter ic'.
If your adc is fast enough, you could sample the AC voltage wave form at greater than twice it's maximum frequency. You could then use dsp maths to calculate the voltage and frequency.
 

elrayes

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adc AC volt

do you mean AC power mains (220v or 110v) or just an AC signal in few volts or milli volts.
for high power AC voltage you will need to use step down transformer or attenuator to read it, for small AC values i think you won't need these things.
 

ark5230

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adc AC volt

If the AC signal is low frequency, much slower than conversiion speed, then it should be posible to read and retrive the AC signal suing fast ADC. Of course the magnitudes are to be taken care.
 

codewiz

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Re: adc AC volt

btbass said:
This depends on the type of reading you want to do?
The simplest way is to rectify the AC voltage and read the resulting DC level, this will give you peak AC volts.
You can get some IC's that convert AC voltages to RMS DC levels. Google 'rms to dc converter ic'.
If your adc is fast enough, you could sample the AC voltage wave form at greater than twice it's maximum frequency. You could then use dsp maths to calculate the voltage and frequency.



I will like to know about the dsp maths. Link or guide to how to learn it will be appreciated. I'm very interested in using PIC to work with AC voltage and feedback controls.
Thanks
 

btbass

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Re: adc AC volt

This is a large subject and very intensely mathematical biased.
Just google 'Digital Signal Processing' and you will get a lot of results.
If you are using a dsPic, the compiler comes with a library of dsp routines you can use. Just look in 'dsp.h' for the function prototypes.
eda board also has a 'Digital Signal Processing' forum you can look at.
 

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