Hello,
I would like to build a constant current source which outputs 150-200mA and which can be controlled through arduino PWM. I have ordered a few higher constant current circuits but they're too high (500-700mA).
I tried googling for schematics, but I don't really know how to calculate the correct values and every time I see a circuit there's attached a comment about fires and failures :o
Context: RGB strip, total: 500mA draw, each color 150-200mA, driven through Arduino
"Dumb" RGB LED strips already have current limiting resistors fitted.
Just PWM the RGB connections with a logic level mosfet to ground.
If you mean someting else, give us the full picture (links, code, etc.), so we don't have to guess.
Leo..
Wawa:
"Dumb" RGB LED strips already have current limiting resistors fitted.
Just PWM the RGB connections with a logic level mosfet to ground.If you mean someting else, give us the full picture (links, code, etc.), so we don't have to guess.
Leo..
This's what I mean, just some basic fading etc.
I don't happen to have a logic level mosfet at hand, but I do have there parts
Wawa:
There is only a non-logic level IRF3205 and a 2N7000 on that list.
Lots of tutorials here.
Leo..
Oh, okay, no way around the logic level mosfets I guess.
Does it matter which one(s) I order?
Yeah, instead of the MOSFETs I was hoping to use similar circuit with 555
Sorry for bumping, but this is not a good idea?
outro:
Sorry for bumping, but this is not a good idea?
Not on an Arduino forum.
You could use a BD135 with 220ohm base resistor instead of a mosfet,
but total LED current will be limited to about 500mA and LED string brightness won't be 100%.
Leo..