Quick question

Do you have to have a massively noticeable dip to confirm ovulation or just a lower temp compared to the next three? I guess a better way to explain. It is like some of the charts that I see show a massively big dip in temperature that practically looks like a V on the chart. Is that the only way it shows. Or can it be any lower temp than the next three?  really hard to explain what I’m trying to say.🤣