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we are asked to construct a pi-type and a t-type band pass filter, with an fr of 15khz and fl of 14khz and fh of 16khz.. so far i have constructed a pi type filter but i still don't get the desired output.. a little help of my calculations please.. thanks.. here is my pi type circuit.. hoping to get help as soon as possible...https://www.circuitlab.com/circuit/799je3/pitype1/

You need to:

1) post the url more carefully:

https://www.circuitlab.com/circuit/799je3/pitype1/

2) add a source impedance (100R?) to drive the pi filter. You can't drive it from a pure voltage source (0R);

3) put your calculations into the component parameters so that people can see and check them easily. They show the value (result of a calculation) on the schematic and the actual sums in the "Edit Parameters" dialogue boxes.

https://www.circuitlab.com/circuit/799je3/pitype1/

i really don't know how to include my calculations in the parameters so, i used nodes instead..

i assumed that the inductor and capacitor (L1 and C1, and L2 and C2) in parallel, though produce lesser impedance, should have greater impedance than the inductor and capacitor (L3 and C3) in series..

https://www.circuitlab.com/circuit/756eyt/ttype-test/ here's another type of bandpass filter.. same requirements.. i still don't know if my assumptions are correct in the previous type,

You need to read about and understand the difference between a voltage source and a current source.

The V and I sources in simulators, unless set otherwise, are pure voltage and current sources respectively.

A pure voltage source has zero source resistance. It will continue to generate the same output voltage across any load that is applied across it's output terminals.

A pure current source has infinite source resistance. It will continue to push the same output current through any load that is applied across it's output terminals.

You also need to understand their equivalent circuits:

http://en.wikipedia.org/wiki/Equivalent_circuit

http://en.wikipedia.org/wiki/Th%C3%A9venin%27s_theorem

http://en.wikipedia.org/wiki/Norton%27s_theorem

https://www.circuitlab.com/circuit/8teegk/thevenin-and-norton-equivalent-circuits-01/

"put your calculations into the component parameters"

"i really don't know how to include my calculations in the parameters so, i used nodes instead.."

It's in the FAQ:

https://www.circuitlab.com/docs/faq/#q_expressions_parameters

Double click on the component or

Right Click > Edit Parameters

Hint:

In:

https://www.circuitlab.com/circuit/799je3/pitype1/

you are showing a load resistance of 100R. What source resistance are you being asked to design the filter for?

our teacher didn't say anything about load resistance.. all he was asking was to create bandpass filters using the T- and Pi - type configuration with fr=15khz..

Did your teacher not mention source resistance either?

Hints:

1)

2) Try setting the load in your circuit to 50R and add a 50R between your voltage source and the input to the filter.

or,

3) Drive the T filter from a voltage source and drive the Pi filter from a current source.

See:

http://electronicdesign.com/communications/back-basics-impedance-matching-part-1

http://electronicdesign.com/communications/back-basics-impedance-matching-part-2

and in particular:

http://electronicdesign.com/communications/back-basics-impedance-matching-part-3