The brightest led diode

[Tosh]

Hi all this is my first post so excuse my ignorance.

I’m currently doing a project where I’m using some 12mm clear Acrylic tubed with a 5mm hole running through the middle, I want to illuminate them with a blue 5mm round head or similar size led diode which I will run of a 12v ac/dc adapter, I have tried using one of those kits made by Ring which is designed for automotive use for illuminating vehicle interiors but it was not bright enough.

So my question is what is the brightest 12v 5mm led diode available or of similar size that I could use? Obviously it can’t be anything that gives off heat, and preferably something pre-wired for simplicity as I have no idea about other components needed to run them in series from a 12v supply, I have looked on line but to no avail.

Thanks in advance for any help given.

 

[Diver300]

All LEDs will produce heat. Brighter ones will produce more heat.

The apparent brightness depends on the beam angle. If you are using the acrylic tube as a light-guide, then you probably want as narrow an angle as you can get to project the light along the tube.

Something like this:- https://uk.farnell.com/multicomp/ovl-5523/led-5mm-blue-4-3cd-465nm/dp/1716703

5 mm diameter LEDs are in a package called T 1 3/4. Those are rarely rated at more than 30 mA so they won't get very hot.

LEDs have to be connected to a current-controlled supply. For one LED from a 12 V adaptor, all you need is a resistor in series. It's not very efficient, and you will get about 3/4 of the power in the resistor and 1/4 of the power in the LED, but it's probably not a problem with such a low power.

There's a calculator here https://mtrak.co.uk/led_calculator.html for the LED current. If you set the maximum current to 30 mA and the minimum to 20 mA it will probably be about right for what you want.

 

[Tosh]

That great thank you for that information & the link that’s most helpful, that brand are cheap enough on eBay so I will give them a try to see if there’s much difference with the ones I’ve got.

Do you mean place the appropriate resistor in series at each led or just one in the circuit?

cheers

 

[Diver300]

If you have several LEDs in series you only need one resistor for all the LEDs that are in series.

With blue LEDs, the voltage is around 3V so you can’t have more than 3 in series, giving a total of 9 V, with a 12 V supply. If you need more than 3 LEDs, you need more than one series group, and each series group needs a separate resistor.

 

[Tosh]

Thank,

I will have four in total in total so will split it into two groups.

much appreciate.

 

[audioguru]

The absolute maximum continuous current for that one and most other 5mm LEDs is only 30mA but less in a car in the sun in summer. So it will not be very bright.
Its beam is so narrow that it will make only a tiny dot of light.
ebay sells fakes and defective "sweepings from a manufacturer's floor". Buy electronic parts from a real, genuine and local electronic parts distributor.

 

[Tosh]

If I could pester you guy’s again, the new Multicomp Pro OVL-5523 have arrived so I’m looking to use the existing wires from the old led’s which have the Resistors on them.

So if you can excuse my ignorance could you please run your eyes over the diagram & details to let me know it will be ok.

So hopefully these will be a fair bit brighter!

I.T.E. Power supply
Input: 100-240v ~50/60 Hz 0.2A
Output: 12v … 0.5A

These are the Ristors already attached

 

[Diver300]

That connection looks fine. It's a 560 Ohm resistor so it'll give about 16 mA per LED

The circuit doesn't actually show which way round the LEDs are. The diagram assumes that the resistors ares soldered into the +ve leads.

 

[audioguru]

Did you test the LEDs yet to see the narrow light beam?

 

[Tosh]

That connection looks fine. It's a 560 Ohm resistor so it'll give about 16 mA per LED

The circuit doesn't actually show which way round the LEDs are. The diagram assumes that the resistors ares soldered into the +ve leads.

thanks for that.

Yes that’s correct the resistors are on the + side.

Am I correct in saying that this set up can’t be improved on in the way of making the led’s brighter?

 

[Tosh]

Did you test the LEDs yet to see the narrow light beam?

Thanks Yes,

i have checked one out of the pack and it was a little bit brighter & as said the beam was narrower & more directional, I will check each individual one before soldering

 

[Diver300]

Am I correct in saying that this set up can’t be improved on in the way of making the led’s brighter?

You can put smaller value resistors. If you put half the value, you will get twice the current, and about twice the light.

I don't know what the maximum current rating for the LEDs is. They will have a very short life if the current is increased beyond the maximum rating.

 

[audioguru]

Most LEDs that have a 5mm diameter case have a maximum allowed current of 30mA. Doubling the current causes a little more brightness but a lot less life.
Cheap no-name-brand LEDs sold on ebay and other sites "over there" are old and dim. Modern Name-Brand LEDs are very bright with a wide beam.

 

[Tosh]

Thanks guy’s for your help its much appreciate, it’s a refreshing change to come on a forum with a subject that I have little knowledge on and not be shot down by people, credit to yourselves and this forum.

thanks again
Ken