Thread: What is the difference between a spectroscopic binary and a visual binary?

How is the period of each type found?

Both are binary stars.
The difference is just the way they are observed and classified. One type can be observed visually by by a telescope, while the other type is detected spectroscopically, by looking at the periodic changes in the spectral lines from the orbiting stars. Usually spectroscopic binaries are too close to be split visually.