hello I'm running a 2n2222 transistor with a RGB led strip and a 1k resistor well i have 3 2n2222 transistor one for each color everything is working good but i notice that the 2n2222 are a little warm to the touch not sure why is that can someone help me out?
Joseph
It is warm due to the power it is dissapating. As long as it is only warm then it is fine and nothing to worry about.
If you can't squeeze it between your thumb and forefinger for and hold it for 60 seconds without pulling your hand away then it is ok.
raschemmel:
If you can't squeeze it between your thumb and forefinger for and hold it for 60 seconds without pulling your hand away then it is ok.
No it is fine as long as you can bare to touch it at all. The junction temperature can be up to 150 Degrees C
The thermal characteristics are
Thermal Resistance, Junction to Ambient R JA 200 °C/W
Thermal Resistance, Junction to Case R JC 83.3 °C/W
For information on using these then see:-
http://www.thebox.myzen.co.uk/Tutorial/Power.html
and
http://www.thebox.myzen.co.uk/Tutorial/Power_Examples.html
You may use Resistors or transistor sink. 
josephchrzempiec:
hello I'm running a 2n2222 transistor with a RGB led strip and a 1k resistor well i have 3 2n2222 transistor one for each color everything is working good but i notice that the 2n2222 are a little warm to the touch not sure why is that can someone help me out?Joseph
you have a 220ohm resistor between the output pin and the transistor base, yes?
Or i advice that three transistors should be used for each r ,g and b . [Each pin]
You may use Resistors or transistor sink. smiley-neutral
I think you mean heatsink. The OP hasn't specified whether he is using TO92 case or TO18
2n2222_TO18.pdf (54 KB)
PN2222A_TO-92.pdf (175 KB)
1abel:
You may use Resistors or transistor sink.
Can you explain what you mean by that.
If the transistor is only warm there is no need for a heat sink. I assume that is what you mean by a transistor sink.
I can't see how using a resistor will reduce the power dissipated in the transistor.
you have a 220ohm resistor between the output pin and the transistor base, yes?
He did say 1K. Whether that is low enough depends on the current load which has not been stated. At 150mA the current gain is about 120, so 1K will give a base current of 4.3mA, which is more than enough.
Hello to all this is what i have each color R G B each one haves a 2n2222 transistor the led strip each color led is by its self meaning there is a r led next to is a green led and third one is a blue led all single leds total 300 leds but each color haves a 2n2222 with a 1k resistor on the base of the transistor going to the arduino. from what I'm reading the 2n2222 can only handle i believe is 500ma total i might be mistaking but i don't remember i tested out each color and and each one putting out 850ma. so i know that is the problem there also what else I'm seeing i might need a mosfet and only ones i have are on the package say tip3055 npn not sure if that will work or not.
I'm seeing i might need a mosfet and only ones i have are on the package say tip3055 npn not sure if that will work or not.
A TIP3055 is not a mosfet it is a power transistor. Yes that will probably work as well.
The description you have given of the LED strips are garbled. We need to know how much current each colour is drawing before we can recommend anything. If you do not know post a link to where you got it from.
I'm sorry if i worded it incorrectly the red is putting out 852ma the green is putting out 340ma the red is putting out 362ma the blue is putting out 341ma i just tested with my meter.
To me that sounds fine just the way you have it. Slight warming is to be expected when switching such currents with a transistor.
thank you grumpy mike i used the tip3055 with a 1k resistor and that seems to work even the fading of each color looks more smoothly maybe it's just my eyes playing tricks lol. but i tried and it and it works great. thanks all for the help