A tutor that builds your answer with you
Sparky works like a good senior on watch. It asks what you already know, spots exactly what is missing, and builds the answer from there, one piece at a time, until you can explain it yourself. It sits beside the topic you are reading, at any hour.
- Starts from what you know, so it does not waste your time on what you have already got
- Finds the gap: the one piece you are missing, often the very piece a surveyor probes for
- Builds it brick by brick, one step at a time, until the whole answer stands on its own
- Then tests you like a surveyor, so the oral is not the first time you say it out loud
How we are building it
Sparky answers from the same Elec-Buddy notes and Surveyor Q&A model answers you study, for the topic you have open, so what it tells you matches the course. It keeps to ETO subjects and is being tested topic by topic. While it is in testing it will tell you to check anything important against the notes, and every correction we make to the notes reaches Sparky too.
Why does an insulation tester use DC and not AC?
Let's build it. Picture a long cable: a core, insulation, and the sheath around it. Electrically, what does that look like?
Two conductors with insulation between them... a capacitor?
Exactly, and that is the piece most people miss. With AC, that capacitance keeps drawing charging current every cycle, and it swamps the tiny leakage you are trying to measure. With DC, the charging current dies away in seconds. What is left is the leakage through the insulation, and that is your reading.
Now say it the way you would to a surveyor, in two sentences.