can someone help me choose a good mosfet, i need a enhanced n-channel mosfet for driving a solenoid, id like to send a high signal to the mosfet with an arduino, i already have the circuits built but im having trouble finding the right mosfet. im going to say it needs to be atleast 10a/9v. i will be…

hi, thankyou. can you tell me what Vgss Gate-Source Voltage +20v means? this is on its data sheet. also what exactly does this mean, 32A, 60V, Rds(on)=35 mOHM(max) @ Vgs=10V, id=16a. , thanks, im not sure what they mean when they are talking about the gate? long story short, i bought a fqpf13n50c…

The fqpf13n50c is only rated 6.5A with an on resistance of 450mOhm. Not good enough. The 20v is the absolute max gate-source voltage - not relevant. The FQP30N06L has an on resistance of <50 mOhm at 5v gate drive. So with 10 amps Id it will dissipate about 1/2 watt It'll work fine. Allan

okay so the on resistance will determine how much current the gate will need to turn on? thanks again

i read this, "The on-resistance determines the conduction power dissipation and increases with increasing temperature" but can you tell me what they mean when they say "conduction power dissipation" do the just mean its going to want to use about that much current when fully on at said temp?

Download and read the datasheet. The on resisance at a given gate source voltage dissipates power exactly as a resistor would, and obeys Ohm's law. Things vary with temperature, so you may need to fit a heatsink. Since you're only switching a short pulse this is probably not necessary. Allan

okay so the on resistance will determine how much current the gate will need to turn on? thanks again No. Just to repeat things for clarity, a fet/mosfet is a voltage controlled device, transistors are current controlled. As Allan said, the drain to source resistance varies in proportion to the g…

so then maybe the moafets i have tried to use have too much on resistance and thats why i need to much input at the gate to turn it on enough to work? i need to learn to read the data sheets better.

The usual problem is that many mosfets need 10 volts or more on the gate to reach their rated (lowest) resistance. That's why we have "logic level" mosfets that turn fully on with as low as 2.5 volts. The logic level devices usually have an "L" in their part number.

can someone tell me exactly what the resistance does in a simple-er way please!!!! lol thankyou

Enhanced N-Channel Mosfet selection

Other Hardware General Electronics

allanhurst June 5, 2017, 9:27pm 2

There are lots available for this sort of job.

I often use the FQP30N06L.

Don't forget the flywheel diode.

Allan

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Enhanced N-Channel Mosfet selection

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