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8th Oct 2018, 10:48 am | #21 |
Pentode
Join Date: Jan 2013
Location: Powell River, British Columbia, Canada.
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Re: Peak to Peak - RMS made simple
Most in here will realize a mind gap at the first whiff of smoke.
And will correct it pronto. Say no more Say no more
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Steve Dow VE7ASO |
8th Oct 2018, 11:20 am | #22 | |
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Re: Peak to Peak - RMS made simple
Quote:
If people can't be bothered to make the effort to understand a bit of simple maths that's fine by me, but I wish they wouldn't regard me as some kind of freak because I have made the effort. Sadly "not being good at maths" has become acceptable in this country.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
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8th Oct 2018, 11:36 am | #23 |
Pentode
Join Date: Jul 2009
Location: Roxburghshire, UK.
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Re: peak to peak - RMS made simple
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8th Oct 2018, 11:46 am | #24 |
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Re: Peak to Peak - RMS made simple
Some people do genuinely find mathematical reasoning difficult, particularly the more advanced stuff. I know because I'm one of them. Sometimes I just have to accept that a mathematical proof exists despite my being unable to understand it.
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8th Oct 2018, 12:25 pm | #25 |
Heptode
Join Date: Feb 2006
Location: Marlborough, Wiltshire, UK.
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Re: Peak to Peak - RMS made simple
I find it irritating when "arithmetic" is usually meant when "maths" is referred to, by the media !
Sorry, drifted OT. Ken |
8th Oct 2018, 1:25 pm | #26 |
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Re: Peak to Peak - RMS made simple
I have found some areas of maths quite difficult. I suppose everyone has. But confronted with an unavoidable need, I had to wade in and find a way whereby I could understand it.
I found that looking at the same problem from a variety of directions could cause thoughts to click, when I saw a pattern and how things fitted together. All of a sudden the aura of fear surrounding some area dissipated into a cloud of 'Oh, is that all it is?' and I wondered what all the fuss was about. Problems you haven't solved are always difficult ones. Once you've solved them they seem easy. Maths is taught badly. There isn't enough on what it is for, what you are doing, why you are doing it and how it works. I watched other students on the BSc course I was on running scared from the transform maths in control theory and circuit analysis. Fourier was on their avoidance list, too. With my oddball way of looking at things this looked like a job opportunity. People who didn't rely on doing other optional exam questions would be a rare commodity. I then discovered that the lecturers in these scary subjects set easy questions and marked generously - just delighted that someone answered their question and thereby justified their existence! Maths is a tool for exploring and analysing things we have discovered, but more than that, it can be used to discover new things that we haven't yet come across in reality. An example is to take the simple equations describing a simple R-C lowpass filter. Now play the vandal and do something stupid. Put in the frequency as a complex number and graph the gain of the citcuit over real and imaginary frequency. At some values it explodes. A passive circuit giving infinite gain! any non-zero input will give infinite energy! Crazy, or what? But if you analyse a circuit with complex numbers fro frequency youfind the points of craziness form patterns and those patterns make handy shorthand for analysing and designing circuits and cut out a lot of the tedious maths involved. You just have to be a natural vandal, a presser of buttons labelled 'do not press this button' just to see what happens. Maths can turn into fun and exploration, leaving tedium behind. The sorts of people who can open your eyes rarely wind up in teaching jobs, though. Unless you can get into one of the rare institutions with great teachers, you have to teach yourself. This is a bit of a barrier, but then you don't need to go to one of those institutions David
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8th Oct 2018, 1:44 pm | #27 | ||
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Re: Peak to Peak - RMS made simple
Quote:
Faced with the same problem I say to myself "I need to multiply by the square root of two to convert RMS to peak". I know that the square root of two is 1.414. Then I'd say to myself " I need to multiply the result by two to convert peak to peak to peak". The result of this is 2.828, which rounded down is 2.83 as stated by the OP.
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8th Oct 2018, 1:55 pm | #28 |
Banned
Join Date: May 2018
Location: Norwich, Norfolk, UK.
Posts: 605
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Re: Peak to Peak - RMS made simple
I did understand the math , you are correct . I just didnt KNOW the equation . Now I know you multiply it by the Sqrt of 2 . I can do the math . The other problem I had was that I didnt know how to use the sqrt button on the calculator . Because I had never had too . I unfortunately dropped out of school at 14 because of some health problem I still have (i`m bipolar) so I never took any exams or learned to use one . I can of course use a regular calculator but for a scientific I had to figure it out . Now I have thanks to the folks in the group , I do it that way because its a lot easier and a bit more accurate. I`m certainly not thick , just bipolar ...hehe , once I am able to understand the process , i`m good ..lol
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8th Oct 2018, 4:40 pm | #29 | |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,924
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Re: Peak to Peak - RMS made simple
Quote:
I’m struggling to think of other hobbies where the ability to do maths is as useful as it is with “radio”. Of course, back in the sixties, when many of us got started, the hobby was more limited and so simpler, but now there are challenges like understanding how FET’s can exhibit negative resistance (as discussed in a thread on the forum started by Skywave re building a wideband amp). Then of course, there’s the evolution of SPICE. Inevitably, the gap between senior professional engineers and hobbyist is much wider now than it was 50 years ago, and I think that the need for a mathematical understanding is a key reason for that. Also, time has taken its toll and the maths that I (and perhaps some others?) could cope with ~50 years ago is not what I can cope with now . B
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