Conversion from the ac half wave to the ac full wave

Hello everybody,

Since we can't give negative voltage to Arduino, I can only give the positive half of the ac signal. Can you give me clue about how can I get the complete wave, in other words, how can I display the negative side of the ac signal without changing its frequency ? I am sure for that there must be an algorithm that help me to display the complete signal.

ever heard of a Diode clamper circuit?

Most common way would be to give it an offset. A summing opamp with 1/2 Vcc on the other end is an easy way.

sherzaad:
ever heard of a Diode clamper circuit?

How to Build a Diode Clamper Circuit

Adding offset makes sense but after I did add offset to the signal and subtracted it from the measured value but the equilibrium point of the signal is not centered at zero. I thought voltage drop over the diode might caused it but the difference is much more than the forward breakdown voltage.

burakozat:
and subtracted it from the measured value

Show us how you calculated "it". Hint: it's not 2,V or Vcc/2.