Limiting Power Draw from Underfloor heating system

[EFLImpudence]

That's presumably the idea, and it's quite a common 'tool' that is used.

However, I've often wondered whether it is actually doing people an (educational) service by providing them with such 'tools'. Given an equation as simple as:

X = Y x Z

...it requires only an understanding of the most trivial and basic concepts of algebra to be able to re-arrange it in the other two possible ways (to put Y or Z on the left-hand side) - and the great advantage of learning 'how to do it oneself' is that one can then apply that knowledge to much more complicated equations.

The 'triangles' are a sort of 'cook-book' approach - an approach which (at least in my opinion) rarely has a lot to be said for it.

My reply was an or the answer to Bernard's question:

Why have these confusing triangles ?

Keep it simple Amps = Volts divided by Ohms

So that you can see all three equations at a glance.

View attachment 300060

 

[bernardgreen]

The 'triangles' are a sort of 'cook-book' approach - an approach which (at least in my opinion) rarely has a lot to be said for it.

Agree,

 

[JohnW2]

My reply was an or the answer to Bernard's question:

Yes, I know it was, and in my post (which you quoted) I agreed that your answer to bernard was quite probably 'the explanation'.

However, I went on to essentially agree with bernard's implicit point - namely that it is usually (educationally) preferable to teach/learn basic principles, rather than to rely on the 'cookbook' approach (which can lead to people doing things without necessarily understanding 'why').

Kind Regards, John

 

[bernardgreen]

So that you can see all three equations at a glance.

But why would it be necessary to see all three at a glance. ?

The "cook book" method of imparting information is not education, it is training to do as instructed.

Training works only if the training program includes every possible set of conditions the trained person will encounter.

 

[SpecialK]

You want a solar diverter. Not every load can run off one but resistive heating would be fine.
This guy did kits, he doesn't any more but the site has a lot of interesting info about the concept:

Mk2PVRouter - Introduction

A DIY Constructor’s project to build a Mk2 PV Router system for surplus energy diversion.

mk2pvrouter.co.uk

Brilliant bit of kit if you are good at soldering/basic assembly. Its now sold over at https://mk2pvrouter.com/

 

[EFLImpudence]

It must be a good day with few real problems.

But why would it be necessary to see all three at a glance. ?

Because it is easier.

Whenever I want one of the options, I picture the triangle of letters in my mind.

Do you always write (or picture) V=IR and transfer the required value letter to the other side of the equation?

The "cook book" method of imparting information is not education, it is training to do as instructed.

I agree with that as far as, say, the OSG is concerned but I don't see the relevance to the triangle.

Training works only if the training program includes every possible set of conditions the trained person will encounter.

Like the triangle does.

 

[bernardgreen]

Do you always write (or picture) V=IR and transfer the required value letter to the other side of the equation?

Not always, that said I do sometimes as a check that my recall of the formulas is still correct.

I accept that the triangle method can work for a lot of people but Victory Equals Real Initiative also works as the basic rule from which every other equation can be achieved.

 

[JohnW2]

Do you always write (or picture) V=IR and transfer the required value letter to the other side of the equation?

In other contexts (relating to equations which i don't use 'every day') that is precisely what I would do - remember one equation and then 'transpose' it (either mentally or by scribbling) as required.

In the present context, I don't need to do that, because I use them so often that I "know", without having to think, all three equations - E=IR, I=E/R and R=E/I [ I having been brought of with "E" (electromotive force') rather than "V". ].

I agree with that as far as, say, the OSG is concerned but I don't see the relevance to the triangle.

The 'cookbook approach' is the cookbook approach - whether in the OSG or anywhere else. In my opinion, understanding principles and hence 'being able to think for oneself' is always preferable.

Kind Regards, John

 

[EFLImpudence]

The 'cookbook approach' is the cookbook approach - whether in the OSG or anywhere else. In my opinion, understanding principles and hence 'being able to think for oneself' is always preferable.

How does someone memorising all three equations signify that they understand the principles and are able to think for themselves better than anyone else? Surely that is just 'parrot fashion' learning.

Indeed, what is the difference in memorising all three separate equations and memorising the triangle which contains all three equations?

 

[JohnW2]

How does someone memorising all three equations signify that they understand the principles and are able to think for themselves better than anyone else? Surely that is just 'parrot fashion' learning.

It doesn't. As I said, when one is using then very frequently, then one simply 'remembers' them all, individually, so no need to remember a 'triangle' ... and if one 'remembers' them individually', then the issues we are discussing do not arise..

However, as I said, when equations are less frequently used (and particularly if they are 'more complicated' equations), one will probably not remember all possible transpositions. It's more likely that one will remember just one - and if one has even the most basic understanding of algebra, one can then 're-arrange' the equation to suit one's current need.

As I also said, the great advantage of teaching people to do that, is that they then have the ability to do the same with other equations (e.g. those involving more than three variables), even equations they have never seen before.

Kind Regards, John

 

[RandomGrinch]

But why would it be necessary to see all three at a glance. ?

...mnemonics such as SOHCAHTOA wouldn't work without the triangles.

 

[JohnW2]

...mnemonics such as SOHCAHTOA wouldn't work without the triangles.

Whilst that's true, I'm not sure that example is relevant to this discussion - after all, "SOHCAHTOA" relates specifically to actual triangles (i.e. trigonometry)!

Kind Regards, John

 

[EFLImpudence]

How does someone memorising all three equations signify that they understand the principles and are able to think for themselves better than anyone else? Surely that is just 'parrot fashion' learning.

It doesn't.

Ok.

However, I went on to essentially agree with bernard's implicit point - namely that it is usually (educationally) preferable to teach/learn basic principles, rather than to rely on the 'cookbook' approach (which can lead to people doing things without necessarily understanding 'why').

 

[JohnW2]

Ok.

In terms of the quote from me which you add, it is indeed true that when one gets to the stage of just 'knowing'/'remembering' the equations, one doesn't necessarily know 'why' - and, indeed, one might theoretically be 'remembering' something which is incorrect.

However, I would hope that, in practice, one would not get to the stage of 'just knowing' the equations without, at some point in the past, having satisfied oneself that what one was remembering was correct - and that requires a modicum of mathematical ability.

I agree that, in terms of the Ohm's Law calculations, it's all very trivial - so a lot of what I've said relates more to my experiences of trying to teach people about the use of more complicated (and less frequently used) equations.

Kind Regards, John

 

[DetlefSchmitz]

...mnemonics such as SOHCAHTOA wouldn't work without the triangles.

Apart from the obvious connection, we never used triangular diagrams with that mnemonic, I can't even see how the stupid Ohm's law triangles could even be put to use here.