heater supply (xformer specs are 6.3V 2.5A) as supply for a power LED? - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

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
Reply
 
Thread Tools Search this Thread
Old 15th July 2003, 02:34 AM   #1
jarthel is offline jarthel  Australia
diyAudio Member
 
Join Date: Jan 2002
Location: somewhere in Australia
Default heater supply (xformer specs are 6.3V 2.5A) as supply for a power LED?

as title. Thank you.

Jayel
  Reply With Quote
Old 15th July 2003, 02:42 AM   #2
diyAudio Member
 
JOE DIRT®'s Avatar
 
Join Date: Apr 2003
Location: Brantford, ON
sure why not....a diode and 220 ohm resistor and your good to go
  Reply With Quote
Old 15th July 2003, 04:51 AM   #3
SHiFTY is offline SHiFTY  New Zealand
diyAudio Member
 
SHiFTY's Avatar
 
Join Date: Jul 2002
Location: New Zealand
LEDs don't like AC very much, you would have to rectify it first... Why not use a 6.3V globe or better still, a "pigtail" neon over teh mains...
  Reply With Quote
Old 15th July 2003, 07:02 PM   #4
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
They can take 8PRV.

Tim
__________________
Seven Transistor Labs
Projects and Resources
  Reply With Quote
Old 17th July 2003, 09:38 PM   #5
EC8010 is offline EC8010  United Kingdom
diyAudio Moderator Emeritus
 
EC8010's Avatar
 
Join Date: Jan 2003
Location: Near London. UK
A cheap and cheerful method would be to put a 1N4148 across the LED (in the opposite direction), then add a 1k resistor in series with the whole lot, and bung it across your 6.3VAC. You may find that you notice the flicker, though.
__________________
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...
  Reply With Quote
Old 20th July 2003, 06:17 PM   #6
diyAudio Member
 
Join Date: Jul 2002
Location: South Africa
Simplest - put 1K in series with your LED. No rectification needed. I build like this, and everything works just fine. If you need to know this - for every volt on power supply for LED put 100 Ohms. Higher than that will only dim LED slightly.
Jack
  Reply With Quote
Old 20th July 2003, 06:33 PM   #7
EC8010 is offline EC8010  United Kingdom
diyAudio Moderator Emeritus
 
EC8010's Avatar
 
Join Date: Jan 2003
Location: Near London. UK
Agreed, the LED will self-rectify, and the 1k resistor limits reverse current, but it's a bit naughty. Also half-wave rectification means that you pass DC through your transformer, which is also undesirable. 1N4148 is so cheap (a penny) when you buy 100 that you might as well use it...
__________________
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...
  Reply With Quote
Old 20th July 2003, 08:35 PM   #8
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
Ooooo.. 20mADC on a 3A winding... it won't even notice it's there

Tim
__________________
Seven Transistor Labs
Projects and Resources
  Reply With Quote
Old 20th July 2003, 11:00 PM   #9
diyAudio Member
 
jeffreyj's Avatar
 
Join Date: May 2003
Location: Tampa, FL
If a transformer is not specifically designed to accommodate DC current, then no amount is appropriate. None. It is bad engineering practice, looks shoddy, and, degrades virtually every AC parameter of the transformer to save a measly pence, if that.
__________________
Before you make that audacious claim, check this site out:QAudio Myths
  Reply With Quote
Old 20th July 2003, 11:56 PM   #10
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
Any transformer will tolerate DC. Period. How much depends on construction.

It would be a pretty damned crappy transformer if it couldn't tolerate a mere 1% DC current.

Tim
__________________
Seven Transistor Labs
Projects and Resources
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Power supply cap brands & Specs Zero Cool Everything Else 16 30th October 2010 06:22 AM
FS: chip amp power supply and xformer madisonears Swap Meet 3 3rd March 2009 04:39 AM
Power supply inductors (what specs?) BrianGT Pass Labs 56 20th July 2008 10:48 AM
Heater Power Supply Pspice model ece Tubes / Valves 0 17th July 2007 07:27 AM
Heater power supply help BillyF Tubes / Valves 8 28th August 2003 09:58 AM


New To Site? Need Help?

All times are GMT. The time now is 12:10 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2