Thanks,
My math is in pounds and pence, and we have done it the cheapest way.
Our product range is for architectural use and often only used for one TV set, or for one poccasion/dinner/party etc.
..but still we'd like to have longevity in the product as well as their prettiness.
The power...
IRStuff:
......there's still going to be convection into internal ambient....which transfers heat through the plastic & perspex enclosure to external ambient....i admit its not a great heat transfer path, but its all we have.
IRStuff
....When you say that, do you mean that we should make...
-thanks
Sorry Operahouse, this product was designed by another engineer in the company who is now working on a different project.
-I was simply asked to change a transistor to a cheaper variety on the schematic, -but looked at the product, and noted the lack of "bare" , uncovered aluminium...
LEDs temperature rated to 120C junction.....they are 1W LEDs as i said, but actually its flashing, so, in fact, each of the twelve leds is dissipating 0.6W.
We cant put holes in the enclosure as condensation would get in.
Our margins are too tight and we cant afford hollow aluminium bar.
I...
its till worth convecting heat into the internal ambient, so that the warmed air can flow against the perspex enclosure and transfer heat to it, which will then conduct through the perspex, and then convect from the outer perspex surface to the external ambient.
So we need to get an internal...
the product is enclosed in a plastic and perspex case, so thers no convenient "somewhere else" for the aluminium bar to conduct the heat to.
Our application is constant power, with no transients.
VE1BLL...
You appear to be saying what i am not brave enough to say.........that in fact the...
Operahouse
.....the option of having four copper clad PCBs with no aluminium in the middle does effectively form a hollow metal tube......the metal being provided by the backs of the PCBs.
Otherwise, a hollow aluminium tube actually costs more than a solid one, since it takes more work to get...
Hello,
We have four narrow rectangular LED PCB's, each one comprising three 1W LEDs. These are double sided PCB's with thermal vias to the bottom layer.
Each PCB is mounted on one of the four faces of a vertical, solid aluminium bar...so we have light shining North, East, South & West from...
Hello,
My company has been putting 1A power LEDs from Cree and Osram in parallel for soome time now.
We only ever use a single current source, and NEVER use series current equalisation resistors or current mirrors.
We have encountered no problems......so why is everyone telling us we are...
Thanks:
Comcokid,
..yes but surely the turn on time is a small , tiny interval, and will not be significant in heating the LM350?
When flash is on, the LM350 has 28 - (7.5+1.25 + 3.2*3.9) across it = 6.77V
When flash is off, the LM350 has nearly 28V across it ..but its not conducting...
Hello,
We are in Brisbane and are having big trouble (and angry customers) with a 6.8W flashing LED light which is a warning light…………
The linear regulator (LM350) keeps blowing up (its case is blown wide open).
Here is the schematic.
http://i48.tinypic.com/2cfxwqq.jpg
(the schematic uses...
Hi,
Why do Class D amplifier designers prefer high voltage supply rails?
Please find attached here two Full-Bridge , Class D amplifier simulations which run in the free simulator called LTspice by linear.com.
Each simulation is of a 4KHz sine wave which gives 100W of power in the speaker...
We understand how to measure it, its just that part to part variance is said to be extremely wide, and if we measure it on one part, we've still no idea what is the min and max of any particular batch.
We are in Vancouver and the semiconductor/component reps dont get up to us much too.
hello
do you know what are likely values of the Cpole parameter for this optocoupler?
CNY17-2
http://www.vishay.com/docs/83606/cny17.pdf
I am talking about when there is round 3mA flowing in the opto diode.
I need the full tolerance range....i.e min and max of Cpole.
This optocoupler will...
