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  #1  
Old 4th December 2021, 05:27 PM
pager8 pager8 is offline
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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)
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  #2  
Old 4th December 2021, 07:52 PM
A Stuart A Stuart is offline
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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?
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  #3  
Old 5th December 2021, 08:56 AM
bob orbell bob orbell is offline
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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
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Old 5th December 2021, 10:07 AM
A Stuart A Stuart is offline
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Default Re: Suitable Pot

Haven't looked, but can't help thinking a switch and handful of resistors might be less expensive.
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  #5  
Old 5th December 2021, 10:25 AM
John Caswell John Caswell is offline
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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
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  #6  
Old 5th December 2021, 12:27 PM
pager8 pager8 is offline
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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)
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