> Why do I have Tennis Shoes if I don't play tennis? > Why do they call the pants you wear when you are dressing up, not slacking > at all, "Slacks"? And why do you call it a "driveway" where you *park* your car and call it a "parkway" where you *drive* your car? ----- Original Message ----- From: "Lawrence Lile" To: Sent: Wednesday, February 27, 2002 11:45 AM Subject: Re: [pic] Math Question - Measuring AC Voltage > If you could guarantee you are really measuring for a full cycle, then yes > it won't make any difference where you start. However, starting at a zero > crossing and ending two zero crossings later (both pos and negative cycle) > guarantees you have measured a full cycle and it's easy to do. > > Now, a dumb question. If RMS is calculated by squaring, averaging, then > taking the root, then why didn't the (possibly dislexic) genius that > invented it call it SQUARE MEAN ROOT since that is really the order you do > these things in? > > I guess the answer might be the same as: > Why do I have Tennis Shoes if I don't play tennis? > Why do they call the pants you wear when you are dressing up, not slacking > at all, "Slacks"? > > --Lawrence > > > ----- Original Message ----- > From: "michael brown" > To: > Sent: Wednesday, February 27, 2002 9:58 AM > Subject: Re: [pic] Math Question - Measuring AC Voltage > > > > Doug says: > > > > > There are many ways to measure AC voltages. The most common is RMS > > > which is the usual 220VAC (110VAC USA). RSM voltage is litterally "Root > > > Mean Square", so you square your readings, average them over one cycle, > > > and take the square root. It would help if you could sync your readings > > > to the zero crossings of the power line. > > > > Why would syncing to the line make any difference. As long as he samples > > one complete cycle why would it matter where he started and where he left > > off? > > > > michael > > > > -- > > http://www.piclist.com hint: The list server can filter out subtopics > > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > > > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics