Measuring an AC signal

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Anonymous
Not applicable

Hi,

   

 

   

I have an AC signal with a peak to peak amplitude of 0.5V and a frequency of 25Hz.  I need to measure the RMS value of this signal.  How do I connect this signal to the PSoC and measure the -ve part of the signal.

   

 

   

Thanks in advance for any pointers.

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1 Solution
MR_41
Employee
Employee
First like received

If your signal ground is isolated from PSoC ground, then you can bring out the AGND to an external pin of PSoC and connect the signal with respect to this AGND.

If your signal ground is same as VSS of PSoC, then the signal can be connected to the input of PSoC using a capacitor and biasing the input of PSoC to AGND.  Check out the below article that has more details on both these methods.

Measuring Negative Voltage Using PSoC1

Best Regards,
Ganesh
The PSoC Hacker

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3 Replies
MR_41
Employee
Employee
First like received

If your signal ground is isolated from PSoC ground, then you can bring out the AGND to an external pin of PSoC and connect the signal with respect to this AGND.

If your signal ground is same as VSS of PSoC, then the signal can be connected to the input of PSoC using a capacitor and biasing the input of PSoC to AGND.  Check out the below article that has more details on both these methods.

Measuring Negative Voltage Using PSoC1

Best Regards,
Ganesh
The PSoC Hacker

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Anonymous
Not applicable

Thank you very much for the fast response.  My signal ground is not isolated from the PSoC Ground.  So, I will use the C/R method of feeding the signal to the input of the PSoC.  Thanks again for pointing me in the right direction.

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MR_41
Employee
Employee
First like received

You are most welcome!! Glad to be of help.

   

 

   

Best Regards,

   

Ganesh

   

The PSoC Hacker

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