While modeling my PS for my tube preamp, I noticed I can change the resistance of the capacitors. How do I know what the resistance is 10mOhms----100mOhms make a difference. OR Does it not matter in reality.
I looked up the specs. of the caps and only ESL is listed in nH. (10) Now that's tiny...... so what do I enter?
Thanks Ron
I looked up the specs. of the caps and only ESL is listed in nH. (10) Now that's tiny...... so what do I enter?
Thanks Ron
I think that it might be significant. The ESR of electrolytic capacitors is typically much higher at lower frequencies.
If you really can't find the ESR data, which is frequency-dependent and temperature-dependent, by the way, then maybe you could look at the data that is available for several similar types of capacitors that have the same capacitance value and roughly the same size, from other manufacturers, and just make a guess from that.
You could search at the mouser.com or digikey.com site, for example, and then use the datasheet links and/or the links to manufacturers' websites. Some manufacturers do provide the ESR at 120 Hz, for at least one temperature.
You could measure the ESR yourself. But that's probably not worth doing, in this case, unless you already have the equipment needed and the capacitors.
You might also want to post the makes and models of your capacitors, here, so that maybe someone else could offer more help.
Also, Cornell Dubilier has a cool Java applet that gives extensive modeling data, and ESR and impedance plots etc, for some of their electrolytic capacitors, as well as frequency (and temperature)-dependent spice model netlists. It's at:
http://www.cde.com/applets/CDEspiceApplet/aframe.htm
To use it, you'll probably need to go to their site to look up part numbers, first.
I posted some information about using that applet's output for frequency-dependent capacitor modeling in LTspice, in message #136 of the thread at the following link. And there is a LOT of other good capacitor information, in that thread. It's at:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=106648&perpage=25&highlight=&pagenumber=6
Good luck.
- Tom Gootee
http://www.fullnet.com/~tomg/index.html
If you really can't find the ESR data, which is frequency-dependent and temperature-dependent, by the way, then maybe you could look at the data that is available for several similar types of capacitors that have the same capacitance value and roughly the same size, from other manufacturers, and just make a guess from that.
You could search at the mouser.com or digikey.com site, for example, and then use the datasheet links and/or the links to manufacturers' websites. Some manufacturers do provide the ESR at 120 Hz, for at least one temperature.
You could measure the ESR yourself. But that's probably not worth doing, in this case, unless you already have the equipment needed and the capacitors.
You might also want to post the makes and models of your capacitors, here, so that maybe someone else could offer more help.
Also, Cornell Dubilier has a cool Java applet that gives extensive modeling data, and ESR and impedance plots etc, for some of their electrolytic capacitors, as well as frequency (and temperature)-dependent spice model netlists. It's at:
http://www.cde.com/applets/CDEspiceApplet/aframe.htm
To use it, you'll probably need to go to their site to look up part numbers, first.
I posted some information about using that applet's output for frequency-dependent capacitor modeling in LTspice, in message #136 of the thread at the following link. And there is a LOT of other good capacitor information, in that thread. It's at:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=106648&perpage=25&highlight=&pagenumber=6
Good luck.
- Tom Gootee
http://www.fullnet.com/~tomg/index.html
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