World-Designs-Forum  

Go Back   World-Designs-Forum > World Designs > General
Register FAQ Members List Calendar Gallery Today's Posts Mark Forums Read

General For anything else WD or hifi

Reply
 
Thread Tools Display Modes
  #1  
Old 4th December 2021, 05:27 PM
pager8 pager8 is offline
Member
 
Join Date: Mar 2013
Location: Bristol
Posts: 30
Default Suitable Pot

Hi All.
I am looking for a suitable potentiometer to control the brightness of 3mm LEDs assumedly wire wound, 6v-9v input controlling down to 2v-3v. What value would I need to look at?
Thanks in anticipation
Pager8 (Geoff)
Reply With Quote
  #2  
Old 4th December 2021, 07:52 PM
A Stuart A Stuart is offline
Senior Member
 
Join Date: Jan 2006
Location: Selkirk, Scotland
Posts: 403
Default Re: Suitable Pot

I think we need to know more.
Do you know what current they draw, both maximum rated, and at the minimum brightness you will require?
Also their nominal forward voltage drop?
Is this supply 9V ac or dc?
Reply With Quote
  #3  
Old 5th December 2021, 08:56 AM
bob orbell bob orbell is offline
Senior Member
 
Join Date: Nov 2009
Location: kettering northants.
Posts: 2,734
Default Re: Suitable Pot

Geoff, Richard put a chart on here some time ago for the required resistor, or do you want to have the option to adjust the the LED to different levels. Bob
Reply With Quote
  #4  
Old 5th December 2021, 10:07 AM
A Stuart A Stuart is offline
Senior Member
 
Join Date: Jan 2006
Location: Selkirk, Scotland
Posts: 403
Default Re: Suitable Pot

Haven't looked, but can't help thinking a switch and handful of resistors might be less expensive.
Reply With Quote
  #5  
Old 5th December 2021, 10:25 AM
John Caswell John Caswell is offline
Super Moderator
 
Join Date: Dec 2005
Location: Wokingham, Berkshire
Posts: 1,780
Default Re: Suitable Pot

A pot will not adjust the brightness of an LED as it is a diode. It is either on or off. You would need to make some sort of digital control to to switch it on/off in varying mark space ratios, ie as lamp dimmers do.
That said there are quite a few LED types from ultra bright to dim on the market, you have just got to find them!

John
Reply With Quote
  #6  
Old 5th December 2021, 12:27 PM
pager8 pager8 is offline
Member
 
Join Date: Mar 2013
Location: Bristol
Posts: 30
Default Re: Suitable Pot

Thank you all for your replies, What I was looking for is a way of dimming the brightness of a blue LED to match others, I have several in different Amps etc fed from supposedly 6,3 volts and they are at different brightness levels once resistance is determined I would fit appropriate resistor (Or am I misreading the problem)
Regards Pager8 (Geoff)
Reply With Quote
Reply


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
Forum Jump


All times are GMT +1. The time now is 06:55 AM.


Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright World Designs