Hi,
I want to control ~150 SMD5050 LEDs (and 50 WS2811) with my UNO.
I got some Toshiba K3878 transistors but I am not shure if I can use them... (there is so much info on this sheet)
http://www.toshiba.com/taec/components2/Datasheet_Sync/201005/DST_2SK3878-TDE_EN_12100.pdf
What is the maximum currency these transistors can endure? How much do 150 LEDs drain? And what is the Voltage with which I can/should open the gate?
Soory for these noob questions :S
Thank you!
How much do 150 LEDs drain?
150 times as much as one if in parallel. How much does one drain - you didn't tell us.
The 2SK3878 is a horribly poor performance device and not logic-level, entirely wrong.
You want a low on-resistance, logic-level, modern MOSFET.
(Actually the 2SK3878 is probably a superb performer at 750V, which is what its good at,
but totally wrong for low voltage)
Its specified as 1.3 ohms worst-case at Vgs=10V. You want a device more like 0.01 ohms at
Vgs=4.5V.
What power supply voltage are you using? Can you run the LEDs in series strings? What
actual LEDs are the 5050 SMT ones?
Bought the LED strip from a Chinese seller, not much information there (except the strip is running on 12V) and "LED type: SMD 5050".
So I suppose: http://e-radionica.com/productdata/RGB5050LED.pdf
I bought without power supply so I have to find/buy one if I know how much the controllers + LED will need.
I believe the WS2811 is a driver chip, so you don't need any transistors if you are driving LEDs with it.
Bought the LED strip from a Chinese seller, not much information there (except the strip is running on 12V)
That's usually a very-bad start...
If you buy stuff from reputable suppliers you can get a manufacturer's part number and/or datasheet. Sites like Adafruit and SparkFun usually have that plus additional information.
Sometimes you can get-away with no specs or datasheet if you really know what you are doing or unless you are a really good "hacker" and good at "figuring things out" and "making it work", but there are always risks with that.
Take a picture of one section of the strip (between two cut lines), and post it.
Leo..
No point with the pictures, its a 12V LED strip, the only important thing is measuring
the current it draws at 12V.
I have a 12V/2A power supply from another (shorter) all-in-one LED strip, do you guys think that 2A is enough for 150 LED? (i dont want to fry the supply)
And how do I measure the current drawn when all LEDs are white when I cannot talk to the controllers? Whithout data input the LEDs remain off.