Low frequency cutoff calculation for Noninverted.

5150ed · 8th August 2006, 08:52 AM

Can anybody explain how to calculate the lowfrequency cutoff of input capasitor for inverted GC?

I commonly found the 4.7mf input cap for noninverted schematic but I already a pair of 1mf of very good cap, is the value is too low?

jaudio · 8th August 2006, 08:58 AM

159155/(resistance * frequency)

5150ed · 9th August 2006, 02:12 AM

hmmmm..... I do not quite get it.

Do u mean? 159155/(resistance * frequency)= capasitor value

gengcard · 9th August 2006, 03:33 AM

The low frequency cuttoff is 4Hz, so you can calculate the DC blocking capacitor by below formula

Ci = 1/(2*PI*f*Ri)

If your input impedance is 22K Ohm Ci should be 2.2uF by the formula.

gengcard · 9th August 2006, 03:36 AM

159155 = 1000000/(2*pi)

The formula unit is microfarad.

5150ed · 9th August 2006, 03:57 AM

Thank a lot.

But what is PI???

Greg Erskine · 9th August 2006, 07:32 AM

22/7

jaudio · 9th August 2006, 10:05 AM

I tried both formulas or formuli. I got 1.80uf.

ppcblaster · 9th August 2006, 12:43 PM

Quote:

Originally posted by 5150ed
Thank a lot.

But what is PI???

Sherman · 9th August 2006, 02:04 PM

Quote:

Originally posted by 5150ed
Thank a lot.

But what is PI???

Technically it is the ratio of the circumference of a circle to its diameter. It is an 'irrational number', when the division is carried out it never ends and never repeats.

For all practical purposes in these formulas just use 3.1416.

8th August 2006, 08:52 AM	#1
5150ed diyAudio Member Join Date: Jul 2005 Location: BKK	Low frequency cutoff calculation for Noninverted. Can anybody explain how to calculate the lowfrequency cutoff of input capasitor for inverted GC? I commonly found the 4.7mf input cap for noninverted schematic but I already a pair of 1mf of very good cap, is the value is too low?

9th August 2006, 07:32 AM	#7
Greg Erskine diyAudio Member Join Date: Jan 2002 Location: Sydney/Australia	22/7 __________________ Greg Erskine

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8th August 2006, 08:58 AM	#2
jaudio diyAudio Member Join Date: Oct 2004	159155/(resistance * frequency)

9th August 2006, 02:12 AM	#3
5150ed diyAudio Member Join Date: Jul 2005 Location: BKK	hmmmm..... I do not quite get it. Do u mean? 159155/(resistance * frequency)= capasitor value

9th August 2006, 03:33 AM	#4
gengcard diyAudio Member Join Date: Jun 2004 Location: Bangkok	The low frequency cuttoff is 4Hz, so you can calculate the DC blocking capacitor by below formula Ci = 1/(2PIf*Ri) If your input impedance is 22K Ohm Ci should be 2.2uF by the formula.

9th August 2006, 03:36 AM	#5
gengcard diyAudio Member Join Date: Jun 2004 Location: Bangkok	159155 = 1000000/(2*pi) The formula unit is microfarad.

9th August 2006, 03:57 AM	#6
5150ed diyAudio Member Join Date: Jul 2005 Location: BKK	Thank a lot. But what is PI???

9th August 2006, 10:05 AM	#8
jaudio diyAudio Member Join Date: Oct 2004	I tried both formulas or formuli. I got 1.80uf.

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