[sdiy] Wanted: non mathematical description of the functionofRC-filters

[Thomas Strathmann]

On 06.08.13 21:14, David G Dixon wrote:
> I agree with you, to a degree.  The math needs to come after the concept.
> However, in the case of an RC filter, the concept is of a voltage divider
> where one of the "resistors" has a frequency-dependent resistance.  None of
> this is going to make sense unless a current balance is drawn around the
> central node of the divider.  This, quite simply, requires some math!
> However, it is not much more than arithmetic.

Agreed. In the electronics lecture I was subjected to at university the
RC filter was something we did as an example in preparation for the
final exam. It's quite basic if you know just a little bit about
electronics.

> If someone wants to understand RC filters, but isn't even prepared to do the
> simple math around a voltage divider, then I would say that they simply
> aren't invited to the club.  Sorry, call it elitism if you will, but a
> modicum of effort must be made with these things.

The good thing about almost all matters of learning is that it's not a
club. If it were I wouldn't be interested in learning things and
improving my understanding. But I'm also a firm believer that it's not
the math that is hard but the way it is taught sometimes. I'm not a
believer in dumbing things down to a cookbook approach (although that is
in my experience exactly what engineers do), I just don't think that
everybody needs to have the same level of understanding. Sometimes a
glimpse at the truth is just enough, just like you to KVL and KCL
instead of Maxwell for example. For me the voltage divider "model" is
good enough to work with, for someone else it might be an analogy to a
suitable mechanical system. Sorry, if I come across as a little
self-centered and arrogant in what and how I write. Higher education is
a topic I care deeply about -- it's nearly impossible for me to resist.

	Thomas