i’ve a strange behavior with my rgb led strip. i tested following circuit:
My green LED is always active, like 100%. It’s just the green one, I constructed the circuit twice and getting the same issue again. The green LED lights up every time. The “-” from the external voltage is connected with all 3 transistors and with the GND from the arduino. When i set via Arduino the Color to red, it’s not red it’s Red/Green. Because the Green one still lights up. I tested the circuit once more and i see no error in it. Can anyone tell me, why my green led always lights up?
best wishes! per
I tested the circuit once more and i see no error in it. Can anyone tell me, why my green led always lights up?
It is either a hardware problem (failed transistor) or a software problem (bad sketch).
Did you try swapping the Green transistor for one of the two known to work? Does the problem move with the transistor? If so, you have a failed transistor.
With the wires from the arduino out puts not hooked up does the led bar still light green? This may be a bad transistor.
Try hooking a 10K ohm pull down between the base and ground then leave the arduino outputs unhooked and power it on are they still on green?
Thank you for your fast answers!
It's definitely an hardware problem, since the software is working fine! Im not sure if it's the same transistor as earlier, because i just put them again. Would be kinda unlucky if i got the same one...
@drksam: Yes, i hadn't connect the wires to the arduino, it's still lighting green. I don't know from where the green LED get's the voltage. Looks like the transistor is broken, isn't it?
Because it's the same wiring to red/blue - so there's no difference.
K how about swapping the green transistor with another? And it may be possible that the transistors are a little small ( i dont know what kind you are using).
@drksam: I swaped the old one, he was broken!. It's working now! Thank you!
@johnwasser: Thank you too!
So the next question was what fried the transistor? Is it a suitably rated device
for the LED strip in question? If not you risk getting more failures in the future...