How do I design an active BJT fliter?

Thread Starter

raedshaher8

Joined Dec 22, 2022
11
I have to design a low pass filter using a BJT. I looked everywhere but can't find any proper information. The filter must have a gain of Av=10 with a low cutoff frequency of 10.6kHz. I can design a class a bjt amp with the required gain and I also designed the low pass filter. But I have no clue how to make them into one circuit. Any help is appreciated.
 

crutschow

Joined Mar 14, 2008
34,834
Make it in two stages.
One stage can have the gain of 10.
The other stage is the low-pass filter .
One stage drives the other stage in series.

What is the required filter roll-off characteristics (number of poles, etc.)?
 

Thread Starter

raedshaher8

Joined Dec 22, 2022
11
Make it in two stages.
One stage can have the gain of 10.
The other stage is the low-pass filter .
One stage drives the other stage in series.

What is the required filter roll-off characteristics (number of poles, etc.)?
When you say two stages you mean two sperate BJTs right?
And there isn't really a requirement for roll-off characteristics. I'm thinking just 1 pole should be enough.
 
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