You have a typographical error in the description of figure b located about 1/3 way down the page.. It is the third "figure b" in the article.
You have "(b) Calculation of voltage drips and current."
but it should be "(b) Calculation of voltage drops and current."
Ken Braswell
You have "(b) Calculation of voltage drips and current."
but it should be "(b) Calculation of voltage drops and current."
Ken Braswell