Having trouble with F3 current source - diyAudio
 Having trouble with F3 current source
 User Name Stay logged in? Password
 Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read Search

 Pass Labs This forum is dedicated to Pass Labs discussion.

 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
 23rd August 2008, 05:34 AM #1 diyAudio Member   Join Date: Mar 2002 Location: n/a Having trouble with F3 current source Hey all. I'm currently applying power to my F3 boards, and I'm having trouble setting the current source. I understand that the percentage is supposed to be the ratio of current through the output resistor to the ratio through the aleph resitors. So what I've got, I measuring the AC voltage across resistors R6/R7/R8 (which make 0.4 ohm), and the output resistor R9 (0.47 ohm). Here's what I get : drop across r6/r7/r8 = 0.206 V 0.4 / 0.206 = 1.94 A drop across r9 = 0.35 V 0.47 / 0.35 = 1.35 A 1.94/1.35 *100 = 140 % !!!!!!!! That's not right ... No matter what I set P2 to, the current through the aleph resistors is alway greater than what's going though the output resistor. Any idea where I may have gone wrong ?
 23rd August 2008, 06:10 AM #2 diyAudio Member   Join Date: Apr 2002 Location: SE Washington State Should'nt the voltage drop across R6,7,8 be .66 volts, the emitter base junction of Q4?
 23rd August 2008, 06:27 AM #3 diyAudio Member   Join Date: Mar 2002 Location: n/a Sorry everyone. Please delete this thread, or make it a sticky, as a permanent reminder of Ohm's law. My calcs should have been along the lines of 0.204 (V)/0.4 (ohms), rather than 0.4 / .204 ..... *smacks head*

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are Off Pingbacks are Off Refbacks are Off Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post tschrama Pass Labs 4 29th July 2005 12:55 PM tinkerbell Solid State 35 11th April 2005 11:34 PM capslock Solid State 1 28th February 2003 12:54 PM macka Pass Labs 9 20th May 2002 08:58 PM harvardian Pass Labs 49 6th May 2002 02:44 PM

 New To Site? Need Help?

All times are GMT. The time now is 07:11 PM.