How Do You Know if a Circle Is Opened or Closed on a Number Line?
Thelinesymbolmeans“poweron”andthecirclesymbolmeans“poweroff”.Thepresenceofboth(I/O)onapushbuttonmeanstheswitchtogglesthepower.,Isn'titfromcircuitdiagrams?Thelinemeansit'sconnectedandtheomeansit'sopen.,Thesymbolisalineabdcircleandtheywereoriginall...。參考影片的文章的如下: