Capacitor type in low pass filter

[ajmartin01]

Beginning to build a sine wave generator for 1KHz sine to test amplifier circuits for distortion. I have several examples I will be working from. The idea is to have ultra low distortion in the 0.005 or better range. My question is in the low pass filter of the Op Amp circuit what is the best capacitor type , Ceramic, mica, Polyester film? Yes I know the choice of Op Amp is critical for low distortion, I have several Burr Brown op amps that will more than meet the spec, so really the question is strictly about the capacitor.

Thanks for reading!

Alan

 

[kellys_eye]

Ceramic and mica are generally reserved for higher frequencies than the kHz range - you will be limited by the absolute minimum values required which will take you into the polyester, polypropylene, MLCC types.

Check this out:

https://www.elektormagazine.com/index.php/files/attachment/326

 

[Harald Kapp]

(Almost) anything but no electrolytic. Don't even think of it.
[Edit] When using MLCCS, note that these can show piezoelectric effects. In this article the "singing" of ceramic capacitors is described. There is also the inverse effect: mechanical stress can induce voltages in this type of capacitors which will show up in the output of the filter. You may want to avoid this effect by using film capacitors.

 

[ajmartin01]

Ceramic and mica are generally reserved for higher frequencies than the kHz range - you will be limited by the absolute minimum values required which will take you into the polyester, polypropylene, MLCC types.

Check this out:

https://www.elektormagazine.com/index.php/files/attachment/326

Great article, very close to one of the circuits I was going to be working from. I was in fact going to NOT use the lamp you see in many of these circuits and use another approach. After reading this article I will start with the lamp idea and experiment from there. The answer to the capacitor question is Polypropylene film. Thanks much!

Alan