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Active filters in parallel

fbchurch2009

Jan 10, 2010
17
Joined
Jan 10, 2010
Messages
17
Hello,

I am in the process of building these three narrow bandpass filters (see schematic) I chose different values for each of the components (R1, R2, R3, and C). I was just wondering if placing these filters in parallel will change the filter characteristics I initially had? I am wondering because I took some quick measurements of each R1 (which is their 1k ohm resistor) and got a much different values (since all three R1's are in parallel) Will this change my filter characteristics?



http://makezineblog.files.wordpress.com/2010/10/ledcolororgan-schem_r2.gif
 

Laplace

Apr 4, 2010
1,252
Joined
Apr 4, 2010
Messages
1,252
Not sure what you mean by "measurement of each R1" and how that would give different values from other measurements of R1. Nor can I see how the R1's are in parallel. What I can see is that any level adjustment with one of the 20K potentiometers will change the frequency characteristics of all the filters; however, since the resistance change should be small in relation to the 680Ω shunt resistors and the driving point impedance of the 4.7 μF capacitor, the effect should be negligible.
 
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