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22nd August 2012, 11:57 PM  #26861 
diyAudio Member
Join Date: Jun 2006

Seems like these guys gave it the collage try.
AD797 Clone people! Who can make a better one.
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Robert Lounge Audio 
23rd August 2012, 04:37 AM  #26862 
diyAudio Member
Join Date: Apr 2002
Location: Prague

5W.

23rd August 2012, 04:47 AM  #26863 
diyAudio Member
Join Date: Apr 2002
Location: Prague

Over half period of sine. Over one complete period it is zero as Ed has stated.

23rd August 2012, 06:22 AM  #26864 
diyAudio Member


23rd August 2012, 06:32 AM  #26865 
diyAudio Member
Join Date: Apr 2002
Location: Prague

No. 5W for 1kHz/10Vrms sine, 15.9uF capacitor and 10 ohm resistor. Please check the Ed's image, it is really a trivial task.

23rd August 2012, 12:00 PM  #26866 
diyAudio Member
Join Date: Feb 2007
Location: Tashkent

PMA is a winner.
Impedance modulus of the cap is 10 Ohms at 1kHz, but its vector direction is 90 deg down from 10 Ohms of the resistor active impedance. Total impedance modulus of the RC chain is SQRT(10**2 + 10**2) From this we calculate current and power dissipated on R. 
23rd August 2012, 12:37 PM  #26867 
diyAudio Member

Dick,
The reason why it is not just Xc/(R+Xc) is the phase shift when R = C is 45 degrees. I do want to go over vector math in a bit. So who wants to show the Cartesian coordinate system with a 10 ohm resistor and equivalent capacitor value? 
23rd August 2012, 12:47 PM  #26868 
diyAudio Member
Join Date: Apr 2002
Location: Prague

Ed, please do not. What fascinates me is the lack of basic knowledge even with renowned people. This is really a 'pub threat.

23rd August 2012, 01:30 PM  #26869 
diyAudio Member
Join Date: Jul 2003
Location: berkeley ca

It isn't just that PMA, many of us are 'rusty' and have not done such mental 'manipulation' for many years. When I first started at Ampex in 1967, for example, I was given the task of manipulating Laplace transforms to generate phase compensation circuits for a NASA quality Instrumentation Recorder that operated up to 120ips. Then, I could do it, and it was fun! Today, I can't remember exactly what I did.
It is best not to get too 'smug' as to what it takes to design good analog circuits. This sort of 'engineering' knowledge isn't what is necessary. 
23rd August 2012, 01:52 PM  #26870  
diyAudio Member

Quote:
I was ushered to the cafeteria, which was initially quiet. Within five minutes it filled with line workers. I soldiered on. The very cold fish of a Human Resources person came to collect the thing at the end of the period. I could already tell that he disliked me intensely after our little chats. I aced it, one of a couple who got a perfect score. When I went over it with Brad Plunkett, he asked me if I were sure of one of the Boolean questions, and when I said yes I was pretty confident, he marked that answer on the sheet he had One of the questions was a cleverly worded one about the voltage at the output of a CR voltage divider with sinusoidal excitation. Many many people got that wrong, including a VP from HarmanMotive, who wiggled and wriggled to insist that he was right, according to BP. 

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