Some VERY interesting LED modules

[noel shelley]

On noel shelley Said:

[…] One thought is to use the heatsink membrane between the LED unit and heatsink. […]

I have never understood why, Noel … but please note that the use of such membranes is explicitly rejected in the data-sheet.

MichaelG.

.

Ref. [repeated for convenience]
https://docs.rs-online.com/3995/0900766b8161ece2.pdf

 

[Michael Gilligan]

On Michael Gilligan Said:

 

 

EUREKA !

THE APPLICATION NOTE :

**LINK**

https://www.mouser.jp/pdfdocs/PLWS3000-Series-Orion-Beam-Forming-Module-Application-Note.pdf

MichaelG.

.

Edit: __ It’s well-presented, and very informative.

Edited By Michael Gilligan on 17/01/2023 07:56:16

Quoted wiith apologies to Les & Robert for my not having properly studied this ^^^

RTFM would seem to be the order of the day !

MichaelG.

[Michael Gilligan]

On Michael Gilligan Said:

I have never understood why, Noel … but please note that the use of such membranes is explicitly rejected in the data-sheet

MY ERROR ^^^ 

It is Thermal Pastes that are explicitly rejected

MichaelG.

.

[noel shelleyParticipant @noelshelley55608]

Thank you Michael, It was because I had studied the data sheets that I am intent on using membrane rather than the paste I have tubes of ! The machined faces of both the heatsink and the LED unit are a very close fit but in an effort to avoid the risk of my lovely LEDs producing strange smelling smoke I would rather be safe. The 3 holding screws will ensure a good contact but a small dob in the middle would do little harm – the risk of paste creep is in the context of a LARGE DOB I fancy ? Time will tell. Noel.

PS what is RTFM ?

[Michael GilliganParticipant @michaelgilligan61133]

Read The Flippin Manual

🙂

MichaelG.

[Robert Atkinson 2]

On Robert Atkinson 2 Said:

I used one for a stroboscope with good results. It was a one-off application so I just lashed up a circuit.

Due to low duty cycle minimal heatsinking was required.

Robert.

Could you provide more detail please Robert?  I’ve been dithering about using one or more of these lights in an attempt to improve on my early high-speed photographic experiments, for which a high speed flash is needed.

I used a camera, flash, Arduino, and microphone to catch events like this airgun pellet destroying some water filled plastic tumblers – can you see the pellet:

Here’s the setup:

Operation: The room is darkened.  Starting the Arduino opens the camera’s shutter in ‘B’ mode.   Firing the pistol is picked up by a microphone connected to the Arduino, which having heard the pistol fires the flash, closes the shutter and puts the lights back on.  The exact timing can be varied by the Arduino, and with luck and judgement the flash catches the event at the right moment.

The method is limited mainly by the flash unit.  The photo flash unit I used controls brightness by reducing the time power is applied to it’s Xenon tube: from memory a few milliseconds.  Faster the better, but a bigger problem is the reduced light output from the flash makes it difficult to get good photos.   I need a faster, brighter flash.  The problem shows up attempting to photograph bursting balloons – the bits fly just too far too quickly for my apparatus:

Plessey’s application note suggests their device could be pulsed fast and maybe with way over-the-top amps.   The app note quotes 400A for 8 to 20uS, though that may be the thyristors not the LEDs!   However, as it’s heat that destroys devices, might work.  I wonder how hard the LEDs could be driven by one very short high amperage pulse and live to do it again!

From your stroboscope experience are these LEDs an viable alternative to a Xenon flash?  And what sort of power supply would I need – I’m thinking fat capacitor with a fast switching transistor, but that feels too simple.  Grateful for anything else that might help, even if it’s bad news like that won’t work!

Ta,

Dave

 

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