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Old 8th Oct 2018, 10:48 am   #21
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Default 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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Old 8th Oct 2018, 11:20 am   #22
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Default Re: Peak to Peak - RMS made simple

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Come on folks, let's not make this complicated for people.

LOL.
What's complicated for some people may be simple for others.

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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Old 8th Oct 2018, 11:36 am   #23
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Default Re: peak to peak - RMS made simple

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Grandad told me how to understand maths: "You know those sums you do at school, the ones like 'if it takes eleven men a month to dig a trench 3' deep, 2' wide and a mile long,
Labourers were obviously more industrious in your Grandads's day, David!
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Old 8th Oct 2018, 11:46 am   #24
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Default 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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Old 8th Oct 2018, 12:25 pm   #25
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Default 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
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Old 8th Oct 2018, 1:25 pm   #26
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Default 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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Old 8th Oct 2018, 1:44 pm   #27
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Default Re: Peak to Peak - RMS made simple

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Quote:
Originally Posted by NorfolkDaveUK View Post
Come on folks, let's not make this complicated for people.

LOL.
What's complicated for some people may be simple for others.

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.
To be fair to the OP he clearly does understand the maths and has simplified an expression.

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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Old 8th Oct 2018, 1:55 pm   #28
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Default 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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Old 8th Oct 2018, 4:40 pm   #29
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Default Re: Peak to Peak - RMS made simple

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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
Yes, but I think we need to acknowledge the fact that everyone has their own limit of ability with maths. Even with the best teachers, some get stuck at O level and others are fine until they try to understand Stephen Hawking.

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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