Hello,
just read the paper on firstwatt.com concerning the filter networks for a constant current source amplifier like F1. But I'm a little bit confused about getting the part values. Therefore can somebody explain it to me so that I an verify my thoughts? Let's say, we want to build an 2nd order Bessel filter with a cutoff frequency of 1kHz and 1K ohm load (just as an example). What re the component values?
Greets,
Raphael
just read the paper on firstwatt.com concerning the filter networks for a constant current source amplifier like F1. But I'm a little bit confused about getting the part values. Therefore can somebody explain it to me so that I an verify my thoughts? Let's say, we want to build an 2nd order Bessel filter with a cutoff frequency of 1kHz and 1K ohm load (just as an example). What re the component values?
Greets,
Raphael
Referring you back to that article, on fig 5A you see a 2 pole
high pass and low pass network (in series) both of which are
set for 1 KHz. You need only multiply the inductance values by
125 and the divide the capacitor values by 125 to scale the 8
ohm load to 1 Kohm. You can use these two networks alone -
each does not require the other. The specific alignment of
can be tweaked with modest variations, and of course you can
multiply/divide values of the inductors and capacitors to scale
the filters to other frequencies.
high pass and low pass network (in series) both of which are
set for 1 KHz. You need only multiply the inductance values by
125 and the divide the capacitor values by 125 to scale the 8
ohm load to 1 Kohm. You can use these two networks alone -
each does not require the other. The specific alignment of
can be tweaked with modest variations, and of course you can
multiply/divide values of the inductors and capacitors to scale
the filters to other frequencies.
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