I know that much of ny material is rather scientific and may be rather hard to understand. I have tried to make it as understandable as possible. Have I succeeded? If you have any questions about anything, please let me know so I can try to clear it up. I included a primer on electricity for that reason. When I was in engineering school, I was with a lot of people smarter than me. They easily understood things that I had trouble with, so I understand what that is like. And of course there are different learning styles and repetition is also important. To me it is all easy to understand and makes perfect sense.But you are not me. I am happy to answer any questions you may have.You can reach me at mark@vackent.com.