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Dear all,

I am using function generator to generat a sine wave signal which pass through wheatstone bridge as described in this link http://ccphysics.us/henriques/p202lab/capfromdistance.htm

anyway the output of the bridge will be a sinewave 10V Peak-to-Peak (it can be reduced to 5V if needed) which is the defrences between the two output pins in the bridge

I want to read the  output value (in the laptop screen) using printserial and readanalog from ardinuo uno

my question is how do I make the connections from the two pins to the ardinuo and is it safe, because I am afraid the signal goes to negative Plus I just need to find the max value or peak to peak value

Moreover, should I use normal code

[Reply #1 on:]

It depends on the function generator you are using, the outputs must be floating with respect to the arduino.
Then you would connect the output through a full wave rectifier with the -ve output of the rectifier to the arduino's ground and the positive output through a potential divider to an analogue input.
However, what size are your capacitors going to be? If they are small, say less than 1nF then there will not be enough current through your wheatstone bridge to drive a potential divider with out undue loading of the bridge circuit. In that case you will need an operational amplifier to buffer the input impedance.

If you said exactly what you want to do and measure then the advice could be less ambiguous.

[Reply #2 on:]

Those instructions call for a 10kHz sine wave - by default the Arduino ADC takes 110us or so to sample, which isn't fast enough.  It can be programmed to go quicker via direct register manipulation at reduced accuracy / noise immunity, but it'll be struggling.