Input & Feedback filters - Page 2

lhwidget · 26th June 2009, 12:17 AM

Thanks Pacific, I appreciate the nudge. (and it's only 454 pages long

)

lhwidget · 27th June 2009, 09:16 PM

I get it now

I was just slow to see it in your equations. Instead of the gain being expressed in simple resistances it should be expressed as impedances of the Rf and Ri, Ci legs of the circuit.

Gain = (Zf + Zi) / Zi, where
Zf = X(Rf) = Rf ohms
Zi = X(Ri) + X(Ci), where X(Ri) = Ri ohms and X(Ci) = 1/(2•pi•f•Ci) ohms

Thanks!

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Using 12AX7 as input with feedback	DamienH	Tubes / Valves	1	17th March 2009 12:44 AM
Feedback/Correction on Gain rather than input?	pilli	Everything Else	1	18th September 2008 09:52 AM
Response modification via Input filters: RFQ	xiphmont	Chip Amps	0	25th February 2008 04:12 PM
Cathode feedback and input impedance	abj1	Tubes / Valves	2	31st January 2007 01:06 AM
input impedance of active filters.q	theChris	Analogue Source	1	25th June 2003 11:07 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

26th June 2009, 12:17 AM	#11
lhwidget diyAudio Member Join Date: Oct 2008	Thanks Pacific, I appreciate the nudge. (and it's only 454 pages long )

27th June 2009, 09:16 PM	#12
lhwidget diyAudio Member Join Date: Oct 2008	I get it now I was just slow to see it in your equations. Instead of the gain being expressed in simple resistances it should be expressed as impedances of the Rf and Ri, Ci legs of the circuit. Gain = (Zf + Zi) / Zi, where Zf = X(Rf) = Rf ohms Zi = X(Ri) + X(Ci), where X(Ri) = Ri ohms and X(Ci) = 1/(2•pi•f•Ci) ohms Thanks!

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)