My current project is to put a 36W 12V LED strip in my bedroom and control it with my Arduino (over the internet but that's another story).
36W/12V = 3A which is of course too much for an output pin of the Arduino.
I'm gonna buy a 12V power supply for the LEDs and control them through a : Logic level MOSFET.
Someone advised me to buy an IRLU8721...
I found it on some US website, they cost something like 1 euro but the shipping is like 50 euro... (I live in Belgium)
I know that I can probably use another MOSFET but they are just billions of them and I really don't know which one to choose...
Is any MOSFET with at least 12V, 3A, N-channel, and "logic level" tag alright ?
Is it better to buy one with a voltage close to 12V or even one with 150V is ok ?
Is there an equivalent MOSFET more popular in Europe than the IRLU ?
Are there big differences between 2S, BU, IRF, IRL, etc. MOSFET ?
I've also seen different versions of the same MOSFET for example IRL540N and IRL540N PBF, what's the difference ?
That's a lot of questions
I'm really new to electronic and your advices will be really apreciated !
"Is any MOSFET with at least 12V, 3A, N-channel, and "logic level" tag alright ?"
Pretty much. I would go with lowest Rds (= low heat generated with higher current) and lowest Gate capacitance (= faster transition from hi resistance to low when turning on (and vice versa for off)) parts you can find.
Use the filtering at www.digikey.com to research parts for comparison.
n-channel mosfet
in stock
FETS (single)
Logic level gate
through hole
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Go down the list, look for qty 1, low Rds, low capacitance, >12V & 3A:
Now look around locally for parts like that.
The letters often indicate the package, leadfree status, things like that. Read the datasheet for the part you select for its details.
I found some IRL540N on ebay that I can get !
"IRL540N logic level N mosfet 100V36A IRF540 compatible"
Here's a link to the datasheet.
I d'ont understand much of it
What is the "Gate-to-Source Voltage" ?
Is it a problem if the "Max Gate Threshold Voltage" is 2V and the Arduino will actually provide 5V ? @CrossRoads, were you talking about the "Input Capacitance" ? Is 1800pF low enough ?
Max gate threshold voltage of 2.0v is good. The key parameter when driving a mosfet with 5v direct from Arduino (through a small series resistor) is Rds(on) @ Vgs=5v and Id >= whatever current you are planning to switch. From that you can work out the steady state power dissipation when the mosfet is turned on (P = I^2 * R).
Either will do, but the 2203 looks better to me for this application - not only does it have lower Rds(on) at logic level drive, it has slightly lower total gate charge as well (high gate charge reduces switching speed).
Try 220 ohm gate resistor - it will protect the Arduino from over current. If you want to PWM really fast you might want to consider something faster, but for simple switching its fine.
Yup, the key parameter of a MOSFET is the Rds(on), this determines how much heat is dissipated for your load (use I-squared-R to calculate).
The MOSFET current rating is usually just the max current it can pass without melting when on a water-cooled heatsink - way higher than the current you can use without active cooling. Expect the current rating to be a lot higher than the current you give it.
Hi guys, I'm curious,
with the IRL8113 driving a +12 volt 16 continuous inductive load, what would i need for a heat sink. I am having a hard time understanding the concepts with heat dissipation and wattage. at what point do i need to heat sink these and How far do i need to go?
That mosfet has Rds(on) = 7.1mohm max @ Vgs=4.5V. Whether it needs a heatsink depends on the current taken by the load, and how often you are switching it on and off. If you are not using PWM, or using slow PWM, then it should be OK up to about 12A with no heat sink. The fact that the load is inductive doesn't make much difference, provided you have a flyback diode connected across the load.
