ESP8266 Community Forum

- Sun Mar 20, 2016 6:03 am #43611 10K Pull downs on the Mosfet gates will have a barely noticeable effect on the Gate voltage. The actual resistor value isn't all that critical, just something that will prevent charge hanging around on the otherwise open-circuit Gate/Source junction.

But you are aware that the IRFZ44N has a threshold range of 2V min to 4V max right? That means you might pick one that would not switch at all at 3.3V! Also, you've really got to spend time studying the datasheet. Those thresholds are quoted for a Drain current of a whopping 0.00025 Amps

VGS.png

What you need to do is a plot for the "transfer characteristic". This will show how the Drain current varies with Gate voltage. Here's the plot for the part you've chosen:

TTC.png

Does it still look suitable now? Sorry to be the bearer of bad news

btw any problem to use GPIO16 as output to trigger the relay as per the last schematic.
and no plan to use any power saving mode

If not using wake from deep sleep then GPIO16 is OK to use as an output. What's odd about the pull-up you got from the Arduino link is that GPIO16 has on-chip pull down (the only pin to have this) and at reset, the GPIO defaults to output anyway. With an external pull-up as shown, setting the pin to an input would make it float somewhere in the middle!

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- Sun Mar 20, 2016 8:04 am #43618 now i'am confused

sorry that new people like me is here to learn and irritate you to get the knowledge

is that mean that IRFZ44N is not suitable for that application (12V RGB LED driver)
mainly i selected it because i saw it in many examples (but i now remember that it was used with 5V arduino not 3.3V)
is so what is the alternative that can handles 24A or more and still run on 3.3V pin from ESP8266
i found STP16NF06L with 1- 2.5 V gate threshold URL Datasheet but the problem is the maximum drain current is just 16A


here is my question is it suitable to be used here ?
what is the alternative with higher drain current ?

i need an other MOSFET that can work with ESP8266 but with less Drain Amps about 4 amps , what you suggest ?

10K Pull downs on the Mosfet gates will have a barely noticeable effect on the Gate voltage. The actual resistor value isn't all that critical, just something that will prevent charge hanging around on the otherwise open-circuit Gate/Source junction.

But you are aware that the IRFZ44N has a threshold range of 2V min to 4V max right? That means you might pick one that would not switch at all at 3.3V! Also, you've really got to spend time studying the datasheet. Those thresholds are quoted for a Drain current of a whopping 0.00025 Amps

VGS.png

What you need to do is a plot for the "transfer characteristic". This will show how the Drain current varies with Gate voltage. Here's the plot for the part you've chosen:

TTC.png

Does it still look suitable now? Sorry to be the bearer of bad news

btw any problem to use GPIO16 as output to trigger the relay as per the last schematic.
and no plan to use any power saving mode

If not using wake from deep sleep then GPIO16 is OK to use as an output. What's odd about the pull-up you got from the Arduino link is that GPIO16 has on-chip pull down (the only pin to have this) and at reset, the GPIO defaults to output anyway. With an external pull-up as shown, setting the pin to an input would make it float somewhere in the middle!

- Sun Mar 20, 2016 8:15 am #43619 If you need a very high drain current MOSFET with low gate threshold, there is the IRLB3034PbF.

- Sun Mar 20, 2016 9:01 am #43622

If you need a very high drain current MOSFET with low gate threshold, there is the IRLB3034PbF.

it looks great up to 195A but triple the price of IRFZ44N , i will need 30 Pcs around 18 USD , but that is OK for this project.

i have other project also with driving LED using ESP8266 but i need a small mosfet about 4-6 Amps and can handle 12V
and with package SOT-223 will be Ok not TO-220.