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24VDC LED on 24VAC power source. Amateur questions.

DavidAlan1062

Sep 22, 2022
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What is the simplest circuit I can use to hook up a 24VDC 3 watt LED ribbon to a 24VAC 20VA power source? I used a 3K resister to dim the LED and stop the flicker is this sufficient? Will it shorten the life of the LED? Or do I need a bridge rectifier or something? And how should it be wired?
Thank you.
 

Martaine2005

May 12, 2015
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You certainly can use a bridge rectifier. But maybe a single diode will also suffice.
Wire in series with one of the AC wires. Or a bridge will have AC and DC written on it. Usually the inner two are AC and outer two DC with + and - labelled.

Martin
 

bertus

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Nov 8, 2019
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Hello,

As @Martaine2005 said, a bridge rectifier would do the trick.
You have the flat ones and box ones.
These are common pinouts for them:
GBU60X_pinout.png
kbpc50 pinout.png

Bertus
 

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  • GBU60X.pdf
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  • kbpc50 series.pdf
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DavidAlan1062

Sep 22, 2022
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Thank you so much for your help.
To dim the brightness of the LED should I put the resistor on the - side of the led or + side?
 

bertus

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Hello,

In a series circuit the order of parts does not matter.
The resistor can be used on both sides.

Bertus
 

DavidAlan1062

Sep 22, 2022
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Can you recommend a resister for this purpose so I get the right one? And what are the different values I go by to dim it more or less?
Thank you,
 

bertus

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Hello,

Do you have a datasheet of the used led?
That way we can see what is needed.

Bertus
 

bertus

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Hello,

When you take 0.4 meter if the strip it will take 11.52 X 0.4 = 4.6 watts.
The max current will be 4.6 Watts / 24 Volts = 0.192 A
As the strip seems to have current limiting build in, you could reduce the voltage by putting some diodes in series in stead of a resistor.

Bertus
 

DavidAlan1062

Sep 22, 2022
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Hello,

Thank you for that. But I don't know about diodes. Sorry I don't know much at all about electronics.
Do you have a name and part number?

David
 

bertus

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Hello,

Diodes of the type 1N4001 to 1N4007 will do the trick.
Those can handle currents upto 1 Amp.

Bertus
 

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  • 1N400X.pdf
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Sunnysky

Jul 15, 2016
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What do you want to compromise with simplicity? max brightness, flicker? fully dimmable. Because you must learn how to follow directions and get a few more parts than diodes, capacitor and a pot will burnout as a dimmer with 200 mA.
 
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