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Wave peek detector connected to a Xbee ADC

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priestnot

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I am trying to connect a current sensor clamp to a xbee ADC IO.

The problem is that the clamp give me values on a sinusoidal form from 0V to 1V. And I need to sample from time to time (30 sec) the peek value of the signal. (to multiply for the constat and get the current value)

So I tried to use the rectifier circuit with a capacitor and a resistor in parallel, but the 0.7Vf of the diode does not let me measure the inferior values, and i cannot apply because the ADC has a reference of 1.2V.

So I searched for a better way to do it add I found the precision wave rectifier: link

So I did a simulation with Qucs and it worked like a charm.
So I assembled the circuit in a test board and wen i connect it to the xbee and read it on the computer it gives me values even when i dont have a current passing on the clamp.

I checked with the oscilloscope and when o i connect the rectifier circuit to the ADC the voltage raises from 0 to a 0.04V.

Can any one help me I do not understand why it raises when i connect it to a ADC input.
 

skogsjanne

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Did the voltage rise when you connected the rectifier to the ADC or did you have an output voltage on the output of the rectifier without the ADC connected?
Do you have a voltage on the ADC input before connecting the rectifier?
Do you get a voltage on the ADC input pin if you connect a resistor with the same value as R2 to the pin?
What voltage do you have between the inputs on the OP-amp?
What components do you use?
 

priestnot

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Did the voltage rise when you connected the rectifier to the ADC or did you have an output voltage on the output of the rectifier without the ADC connected?
Do you have a voltage on the ADC input before connecting the rectifier?
Do you get a voltage on the ADC input pin if you connect a resistor with the same value as R2 to the pin?
What voltage do you have between the inputs on the OP-amp?
What components do you use?

Thanks but i found the problem. It was the ADC that was burned
 

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