I am a total newbie in electronics and don't really know much, but I want to achieve one simple thing and I'm looking for some guidance.
Here's what I want do to:
I want to turn the 12V LED on and off on my RC model, maybe with possibility to dim the LED. My flight controller can output PWM signal and power my Arduino board with 5V. The PWM signal that my flight controller outputs is controlled from my radio, but that is not relevant here. I have a BEC that outputs 12V to the LED.
Now, what external hardware (other than 5V source to power Arduino, 12V source to power LED and the PWM signal input) do I need to make it work? Should I use a transistor? A FET? What type of signal do I have to output from Arduino to the transistor/FET in order for it to open the gate? As I understand correctly, a transistor would only turn the LED on and off. What about a FET? Can it dim the diode?
I'm sorry for such newbie questions and I know that you guys on this forum probably get lots of these, but I just don't understand how exactly everything works and I don't know where to start.
What you need is a logic level gate mosfet. The gate needs to be fully on or the resistance of the drain/source is not at its least so causes heat.
My favourite small mosfet is NTD5867NL. It works with 5v on the gate and handles a few amps with ease. They are cheap. I bought mine from RS Components.
There are others but make sure they are fully on at 5v on the gate.
MOSFETs can be turned on fully or by PWM.
A normal transistor can also be used but has a larger voltage drop across it.
weedpharma:
What you need is a logic level gate mosfet. The gate needs to be fully on or the resistance of the drain/source is not at its least so causes heat.
My favourite small mosfet is NTD5867NL. It works with 5v on the gate and handles a few amps with ease. They are cheap. I bought mine from RS Components.
There are others but make sure they are fully on at 5v on the gate.
MOSFETs can be turned on fully or by PWM.
A normal transistor can also be used but has a larger voltage drop across it.
Weedpharma
Hi Weedpharma!
Thanks for your reply!
How do I make sure that the MOSFET is fully on at 5V on the gate? Where on my Arduino should I connect the MOSFET to open and close the gate? I am have the Spakrfun Pro Micro board: https://www.sparkfun.com/products/12640.
You make sure the FET can be turned in fully with 5V by buying the right sort of FET, it will be in the data sheet as a condition of the Rsd paramater ( resistance between source and drain when on )
Connect the gate to any arduino output through a 120R resistor.
