Do you know any thing about low-pass filter?????????

Question

I need any kind of help as soon as you can..
mostly a pictures of it. if you can refer me to a helful web sites that I can gather information of it please give me..

Answer 1

A low-pass filter can be seen as an electronic 'black box'
Input AC of all kind of frequencies.
Output: only low frequencies.
Used with loudspeakers, the bass sounds are clear; the violins are weak.

Th

Answer 2

Low pass filters are used to pass the lower frequences and block the higher frequences.
The classic low pass filter is the power supply filter used to filter AC out of the DC .
It is constructed with two capacitors and one coil called an inductor. And is placed on the positive side or the ungrounded side or high side of the line.

When constructing a low pass filter for a power supply it is shaped like the greek letter pie.

First a capacitor is connected across the line. i.e. between the positive lead and chassis ground in front of the inductor coil then an inductor coil is placed in series in the positive line then then another capacitor is placed across the line behind the inductor coil. between the positive lead and chassis ground.

The capacitors will block the DC but pass the AC ripple to chassis ground. The inductor coil will block the AC but pass the DC The end result is that the AC ripple will be atenuated giving you a fairly smooth DC with little ripple.

In communications low pass filters are used in conjunction with high pass filters to tune radios and TV.s to a specific frequency. Althiough much like the classic power supply filter the values of the capacitor and inductor are a lot different.
An example of that would be say you want to operate on the 400 MegHz band and block all frequencies above that band.
In that case you would use a low pass filter and calculate the values of the capacitors and inductor needed to block all frequencies above 400 Meg Hz.
There are several different variations of the pie low pass filter. One is the L filter which uses only one capacitor. In less expensive equipment another variation is to use resistors instead of using inductor coils. Still another variation found a lot in digital equipment is low pass intergrated circuit filters and switching filters.
In higher frequency filters what is called tuning cavities is used in place of inductors and capacitors. The length and width of the cavity is calculated at design to function as filters in this case they are usually band pass filters acting as both low pass filters and high pass filters blocking all other frequences except the frequency they are tuned to.
Hope that helps you.

Answer 3

Wikipedia has a very good description of the popular types along with schematics and graphical representations.

http://en.wikipedia.org/wiki/Low-pass_filter

Answer 4

Yes, I know rather a lot about low-pass filters. Also high-pass, band-pass, all-pass, and notch filters.

What I don't know about is exactly what it is that you're asking.


Doug