Why use an LED in CCS?

keantoken · 2nd July 2008, 09:04 AM

I can't comprehend there not being another discussion on this, but I searched and found nothing. So here we go.

What are the benefits of using an LED in a CCS, besides that it looks cool?

- keantoken

Christer · 2nd July 2008, 09:10 AM

Low noise and often an appropriate voltage drop in a single component.

AndrewT · 2nd July 2008, 09:23 AM

and the LED voltage stays near constant with small changes in current and temperature.
And it's cheap (red).

keantoken · 2nd July 2008, 09:28 AM

Will a high-intensity LED work better?

AndrewT · 2nd July 2008, 09:31 AM

test it,
But, I doubt you'll find much, if any, improvement with any other than the cheap red LEDs.

search for the LED tests that are posted on the Forum.

Christer · 2nd July 2008, 09:39 AM

Enjoy

Some noise measurements for LEDs and zener diodes

SY · 2nd July 2008, 11:39 AM

kt, besides Christer's most interesting work, the use of LEDs as CCS references and for cathode biasing is discussed in great detail in Morgan Jones's "Valve Amplifiers," 3rd ed. For a CCS, there are quite a few ways to do the reference, but the LED (besides being stable and low noise) does provide a nice visual indicator for troubleshooting.

2nd July 2008, 09:04 AM	#1
keantoken diyAudio Member Join Date: Aug 2006 Location: Texas Blog Entries: 1	Why use an LED in CCS? I can't comprehend there not being another discussion on this, but I searched and found nothing. So here we go. What are the benefits of using an LED in a CCS, besides that it looks cool? - keantoken __________________ Contribute to the DIYAudio WIKI! http://www.diyaudio.com/forums/every...p-sign-up.html LTSpice wiki with special attention to new users' troubles

2nd July 2008, 09:23 AM	#3
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	and the LED voltage stays near constant with small changes in current and temperature. And it's cheap (red). __________________ regards Andrew T.

2nd July 2008, 09:28 AM	#4
keantoken diyAudio Member Join Date: Aug 2006 Location: Texas Blog Entries: 1	Will a high-intensity LED work better? __________________ Contribute to the DIYAudio WIKI! http://www.diyaudio.com/forums/every...p-sign-up.html LTSpice wiki with special attention to new users' troubles

2nd July 2008, 09:31 AM	#5
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	test it, But, I doubt you'll find much, if any, improvement with any other than the cheap red LEDs. search for the LED tests that are posted on the Forum. __________________ regards Andrew T.

2nd July 2008, 11:39 AM	#7
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	kt, besides Christer's most interesting work, the use of LEDs as CCS references and for cathode biasing is discussed in great detail in Morgan Jones's "Valve Amplifiers," 3rd ed. For a CCS, there are quite a few ways to do the reference, but the LED (besides being stable and low noise) does provide a nice visual indicator for troubleshooting. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache


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2nd July 2008, 09:10 AM	#2
Christer diyAudio Member Join Date: Sep 2002 Location: Sweden	Low noise and often an appropriate voltage drop in a single component.

2nd July 2008, 09:39 AM	#6
Christer diyAudio Member Join Date: Sep 2002 Location: Sweden	Enjoy Some noise measurements for LEDs and zener diodes

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