Electronics > Projects, Designs, and Technical Stuff
How to test a low-impedance filter circuit?
<< < (3/3)
T3sl4co1l:
Yes, quite.  The 50/50 ohm test is the general case, unless we know something more specific, which we do in this case.  An AC current source at the load side would be a more correct model here.

Again, the input isn't doing much (2u rolls off with 50 ohms at >>10kHz), but if you don't mind the use of more inductors, that Q doesn't sound bad, yeah.

Inductors are usually the more annoying part of a design, so one tends to prefer a CLC(LC..) format, with RC damping.

Also, have you considered simply making a longer filter?  You'll get better attenuation with those 330uF's spread out amid, say, three 0.47uH's.  Probably don't even need to be 330, unless there's a hold-up spec you're supporting (in which case, don't forget the diode on the front end, to prevent other loads from discharging it faster!).

Tim
jmw:
You're right, below 4 MHz that 2 uH isn't doing much when in series with 50 ohm. Now I understand what you meant by the transfer function isn't everything: the textbook of course doesn't mention the measurement is taken at the LISN port with its 50 ohm impedance at frequency!
Navigation
Message Index
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod