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How to use TIP127

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My lesson in this is to use a P or NFet in this case; when driving from a PIC with issues of heat and current.


kv
 
"To solve your issue...use a pull up resistor on the PNP base to the 24V supply (4.7k or so should be ok) and rather than outputting a HIGH from the micro to switch the PNP OFF....output a Hi Z (tristate). The additional draw on the micro output is about 5mA when driving low to switch the PNP 'ON'."

You should NOT do this as you are putting more than 5v on the output and the protection diode is being activated.

What is the difficulty with sinking 4mA thru the protection diodes?
I'd think the weakness in the solution IS that the protection diode will pull down the pull up and defeat the intent of the pullup.
 
Hello,
I was searching good branded + Good quality LEDs for Signage purpose for long life span of it.
So, The led should high high bright so that it should be viewed in day light as in led outdoor Video display.
What suggestion to be noted while buying led for signage diffused or clear/transparent ??
minimum intensity? lens types? etc?? to have good result than competitor ?
 
Some cheap "super bright" LEDs from "over there" are simply dim ones in a case that focusses the beam making it concentrated with a narrow viewing angle. Then they cannot be seen a little off axis.
Good quality modern LEDs are very bright over a wide angle.

I have some Lumileds Luxeon Superflux LEDs (made by Philips) that have a 4-pins case. The extra pins are for cooling. They are very bright over a wide angle and their maximum allowed continuous current is 50mA to 70mA which is much higher than ordinary LEDs.
I put 36 of them together at 53mA each for a night light and they light up my entire neighbourhood.
 

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please tell some branded oval led .....
The second site in a Google search:
"This oval LED is specifically designed for variable-message signs and passenger-information signs. The oval-shaped radiation pattern and high luminous intensity ensure that these devices are excellent for wide-field-of-view outdoor applications where a wide viewing angle and readability in sunlight are essential."
https://www.google.ca/url?sa=t&rct=..._dg4AO&usg=AFQjCNGmVLaLSfgqZSAz2P1ekXbEUO85EQ
Don't you know about Google and let it find what you want??
 
Hello the price of king bright, Cree and one more something like avango* was very expensive then i buy packs manufactured from china..
Example the Chinese Red color LED are ~Rs0. 40 to 0.75 /per pcs but these brand sell at Rs 15/. to 48/. per pcs huge difference in cost!
 
huge difference in cost!
There is a huge difference in QUALITY between LEDs made by a name-brand manufacturer and no-name junk from China. Many of the Chinese ones probably will not work or will fail soon.
Name-brand LEDs are bright over a wide angle. Cheap LEDs are focussed into a narrow beam to make them bright only on axis.
 
You show a list of many videos. Which one do you want us to see?
We do not know how dark the lighting is where the sign is so we do not know how bright the sign will be in the daytime.
 
Hello,
here is daytime..

night time

anyway, i got sample from this company https://www.lukeindia.com/
he says its india no1 Company of leds he sends many in round shape diffussed and transparent.
but i will go for oval only...
 
We have huge very bright video screens for advertisements beside highways. They use thousands or millions of LEDs.
All of our traffic lights and street lights are LED ones now, but I can see that some of the LEDs are "burned out".
Each street light has a wireless modem with a little antenna on top.
 
but I can see that some of the LEDs are "burned out"
But i buy new not used one all good, anyway have you seen the link i have sampe from banglore India no 1 led manufacture according to him...
so
 
I do not know if the LEDs from India are any good.
In my city, there is a store that sells surplus electronic items and parts. Everybody working there are from India and many electronic parts are from India. I bought some pretty good name-brand clock radios and modem power supplies at very low prices.
I also bought a bag of blue LEDs (I suspect they are from India, not China) but only half of them work and some of the working ones have visible flaws.
 
Hello,
So, you are suggesting to buy cree leds than these luke !
as comparing the sample i got from manufacture luke it was brigthrer than chinese!
 
Cree is known all over the world as the inventor of the blue LED and as the manufacturer of very high quality LEDs. Nobody except you knows Luke. Did they invent anything?
It is easy to make a dim LED look bright, put it in a focussed case then its beam is concentrated into a narrow angle.
It is also easy to send you their brightest sample. Maybe the range of brightness of their LEDs averages to be fairly dim or maybe some are bright and some are dim.
 
What is the difficulty with sinking 4mA thru the protection diodes?....

We have had this argument before. It is a really bad idea.
 
Hello,
I think you suggestion is excellent, CREE and kingbright like this are well than these!
OK, I will try to buy CREE pls suggests how to promote led Display?
What does this term 1 chip, 2 chip means in LEDs
 
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