Would it be an advantage in terms of admission, to study pedagogics before applying to a PhD? Currently I am in my third year in engineering - applied mathemathics. I have been thinking about what I would want to do after I get my master. I have concluded that I have 3 options.


Work as an engineer.
Study one year pedagogics, then work as a high school teacher.
Apply for a PhD.


In my country you can, if you have a master in engineering - applied mathematics, study one year where most of the studies are pedagogics, and then be considered as any other high school teacher (in math). You will have a master in Teaching.

Since I am not sure of what I really want to do, all three options are "exciting". I want to have as many doors opened as possible. 

So, for example, I could get my engineering degree, then a teaching degree and after that either work as engineering/teacher or apply for PhD.

Therefore I would like to know if it is an advantage in terms of admission, when applying for a PhD, if I have studied pedagogics for one year (right after I have finished engineering school and right before applying). Or would it be preferable to go direct from engineering to PhD, if that is what I want to do.

My location is Sweden. I have not given any thought to which university I would want to do my PhD, but the country would be in Sweden or Germany.
While I have little familiarity with Sweden or Germany, for most technical fields I would see taking a year off to study pedagogy and teach high school would generally provide no advantages and perhaps even be a slight disadvantage for PhD admissions.  I see how it could be an advantage if you want to pursue a PhD in education for example as it gives you relevant practical experience and perspective, but not for most subjects as the primary goal of a PhD program is to train you to be a researcher.

As such, for a PhD, you want to demonstrate passion and dedication to research.  Pursuing another career path first may make some professors question this, and indeed from your question it sounds like you are not totally committed to the research track.  Of course, applying for a PhD program right after a master's doesn't guarantee commitment either and many great researchers got their PhD's after doing other things first. Pursuing teaching next may be the right thing for you if it helps you figure out what you want to do, but I would not recommend it as a way to help you become a PhD student.