im having a hard time finding the right mosfet. i need a mosfet i can drive the the output of an esp8266 pin. it seems like all the ones i have laying around seem to need more power at the gate in order to turn on most of the way. all its doing is running an incandescent bulb about .8 amps at 12v. the best luck i had was driving the mosfet with a pnp transistor which worked untill i fired everything but now im going to buy new parts. can someone help me choose a mosfet/transistor
Hard to find through-hole mosfets for 3.3volt logic, but any logic level fet would work with that low current.
There is no real benefit to use a mosfet for a 12volt/0.8A lightbulb.
I would just use a TIP120 with 1k base resistor.
Datasheet tells me that you only 'loose' ~0.6volt at that current.
Downside is that the TIP120 could get a bit warm.
Leo..
Wawa:
Hard to find through-hole mosfets for 3.3volt logic, but any logic level fet would work with that low current.
There is no real benefit to use a mosfet for a 12volt/0.8A lightbulb.
I would just use a TIP120 with 1k base resistor.
Datasheet tells me that you only 'loose' ~0.6volt at that current.
Downside is that the TIP120 could get a bit warm.
Leo..
thanks that "logic level" mosfet is what i was searching for. i found one on an old pcb works perfect thanks
You can use IRL540 instead of TIP120. TIP120 are darlington pair transistors it is a bit old technology and mightget warm . You can use IRF530 or You can use IRL540(these are logic level ttl and a better choice)
You can alos use these FET drivers https://shop.controleverything.com/collections/high-current-fet-drivers/products/4-channel-8w-12v-fet-driver-proportional-valve-controller
vibhu18:
You can use IRF530 or You can use IRL540(these are logic level ttl and a better choice)
The IRF530/540 are non-logic level fets, and need 10volt gate drive to fully turn on.
That makes them a poor choice for 5volt Arduinos, and useless for 3.3volt Arduinos.
Leo..
You can also buy an adapter board so you can work with smd components.
As has been pointed out, logic level (3.3v) mosfets in through the hole format don't exist. Example:
And in use as a high side switch:
6v6gt:
...
And in use as a high side switch:
That picture should make the guy who is trying to solder a diode to pins with a hollow iron feel better!
Wawa:
The IRF530/540 are non-logic level fets, and need 10volt gate drive to fully turn on.
That makes them a poor choice for 5volt Arduinos, and useless for 3.3volt Arduinos.
Leo..
That's why brother I'm recommending IRL520 or IRL540. This choice is much better than using TIP120 this is old tech, that was a wonder at that time, now we are living in 2018 my dear friend 
That's why brother I'm recommending IRL520 or IRL540. This choice is much better than using TIP120 this is old tech, that was a wonder at that time, now we are living in 2018 my dear friend
I believe you are trying to be helpful... I really do... but these kinds of comments... even when you include a can be misleading.
There are some extremely successful parts in electronics history... this also makes them REALLY common and very accessible and affordable. Maybe we should make it clear that some parts... Like the TIP120 might be "older, but they are still produced and purchased in large quantities. And, they are just as much OVERKILL as the recommended IRL520 or IRL540.
There is NO logical reason for using a 10AMP part for an ~800 milliamp load. The better advice here would be to specify a better transistor for the JOB... and if you are willing add a resistor, it will be perfectly fine to use a bipolar Junction transistor (BJT) ... especially if that's what you have on hand... like a metal case 2N2222a which can handle a 1 amp load in normal use cases.
There is no reason to create disapproval for traditional BJT's... especially for light loads... when BJT's are still in production and very much not obsolete... as you seem to want to indicate.
ChrisTenone:
That picture should make the guy who is trying to solder a diode to pins with a hollow iron feel better!
Well, it was the best I could do with a paraffin blow torch, bar solder and Baker's fluid. But it works and looks fine at magnification 0.
IRF3708PBF is a through hole power MOSFET that works with 3.3v gate drive.
Doesn't the ESP8266 start up with all pins as INPUT_PULLUP? In that case, you'd need to pick a larger pulldown on the gate than usual.
pwillard:
There is NO logical reason for using a 10AMP part for an ~800 milliamp load.
There certainly is for MOSFETs, because you don't choose a MOSFET for its current rating, but
for its on-resistance and package power dissipation.