Interesting T10 LEDs
I found these for less than $2 a pair and they were interesting.
It looked nothing special until I decided to open one up to see what's inside. They used a blue LED and remote phosphor to produce white light. I wanted a warm white version but they did not have any so I settled for these.
These are the T10 bulbs.
They are quite small but light output is spread out and over 180deg out the front.
With the front remote phosphor disc popped off.
Here it is using a blue LED.
With everything apart. Assembly is quite straightforward with minimal parts.
Wait, where is the resistor?
With the LED lit at 100uA.
A micro photo of the LED.
You can see a rectangular whitish block which is the three LED dies in series mounted side by side.
The dark square block on the right is the resistor.
The round thing is an air bubble.
At 100uA, the LED reads 7.6V which means it uses three LED chips in series.
At 18mA, it gets to over 11V.
Calculating with delta V / delta I, the series resistor is about 200ohms.
The phosphor disc fits in front of my 100mW blue laser pointer.
Laser pen torch.
Ran across another type.
This one was advertised as a COB (chip on board) type LED.
The bulbs look high power with the aluminum heatsinks.
It is just press fitted and one resistor came off.
Not high power nor COB. It uses a plain 5mm LED behind a phosphor disc.
The resistors are 56ohms on each leg which totals 112ohms. The LED uses two dies so the result is about 60mA for the whole assembly which I think is too much.
I replaced them with two 100ohm resistors and the current dropped to 30mA which is more manageable and brightness is still the same as the other type above.
This one has a different color beam pattern. The light coming out front has a bluish tinge to it and the ones coming out the sides is yellowish white. Might make an interesting effect on some light housings.
Inspired by all these remote phosphor jobbies, I remembered I got a bunch of these remote phosphor strips way back 2012.
I got a high power aluminum blue LED strip.
These are not ideal as the chromalit strips are meant to be used with royal blue LEDs but we use what we can get.
I machined the edges using the micro table saw to make it fit the rail.
Nice white. It has a very slight blue tint to it but not offensive.
Being a remote phosphor light source, this will, in theory, not fade in long term use.
Light output is great! CRI is not the best but tolerable.
When you look around auto/motorcycle accessory stores you get to see how creative the chinese are in making LED conversions. SMD and COB style LEDs are common but these are the first I saw which uses remote phosphor technology.
Page created and copyright R.Quan ©15 Jan 2017.