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

[Dave Manley]

Consider also the two extremes - operation at DC and at high frequency.  I think Neil Johnson mentioned this in another thread recently.  In one case the cap looks like a short and in the other like an open.

Ex. At DC an RC LPF looks like just a resistor in the signal path since the cap is effectively open.  At high frequency the cap looks like a short to ground.  In the former the signal comes through unattenuated, while in the later no signal comes out.

If they understand the two endpoints then with some "hand waving" you can explain that the values of the R and C determine how the filter behaves in between the two endpoints.

The HPF is similarly easily explained.

-Dave

m brandenberg <mcbinc at panix.com> wrote:
>On Mon, 5 Aug 2013, Florian Anwander wrote:
>
>> Any better ideas?
>
>If you can introduce the idea of a voltage divider of two resistors
>in series, you could then take them along another step where one of
>the resistors varies with frequency.  Now you have RC high- and
>low-pass filters (ignoring phase, complex impedance and superposition).
>
>m
>
>--
>Monty Brandenberg
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at dropmix.xs4all.nl
>http://dropmix.xs4all.nl/mailman/listinfo/synth-diy