Rich330
01-12-2014, 07:20 AM
I have bought a loose 5mm LED to use in a future build as an accent LED, running it off the 3.3V accent pad of a Nano Biscotte.
It's specs are 3.0V forward voltage / 20mH current, so I will be requiring a 15 ohm resistor rated for 1/8W or more.
I'm sourcing the resistor locally and just have the following general (beginner's) questions.
This is what I think I've figured out. Please correct me if I'm wrong ...
I understand that the wattage rating indicates how much power the resistor can dissipate as heat. In layman's terms this means that the a resistor with a higher wattage rating is going to be "safer" for higher power levels, i.e. it's going to take a lot more power to make it overheat and burn out.
This is why the "LED Center" calculator recommends a minimum wattage for the resistor.
As long as you have a resistor with an equal or higher rating to the recommended rating, you are fine.
Apart from the actual size of the resistor (it will be larger) there is no disadvantage to using a resistor with a higher wattage rating. Is this correct?
The local electronics shop has 15 ohm resistors with 1/4W, 1/2W, 1W and 2W ratings. I can safely use any of them can't I? And it's not going to be critical whether I get the 1/4 W or the 2W? Right?
Thanks in advance and please note that I have ordered myself a copy of "Electronics For Dummies" to cut down on these kind of questions in the future! :D
It's specs are 3.0V forward voltage / 20mH current, so I will be requiring a 15 ohm resistor rated for 1/8W or more.
I'm sourcing the resistor locally and just have the following general (beginner's) questions.
This is what I think I've figured out. Please correct me if I'm wrong ...
I understand that the wattage rating indicates how much power the resistor can dissipate as heat. In layman's terms this means that the a resistor with a higher wattage rating is going to be "safer" for higher power levels, i.e. it's going to take a lot more power to make it overheat and burn out.
This is why the "LED Center" calculator recommends a minimum wattage for the resistor.
As long as you have a resistor with an equal or higher rating to the recommended rating, you are fine.
Apart from the actual size of the resistor (it will be larger) there is no disadvantage to using a resistor with a higher wattage rating. Is this correct?
The local electronics shop has 15 ohm resistors with 1/4W, 1/2W, 1W and 2W ratings. I can safely use any of them can't I? And it's not going to be critical whether I get the 1/4 W or the 2W? Right?
Thanks in advance and please note that I have ordered myself a copy of "Electronics For Dummies" to cut down on these kind of questions in the future! :D