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3ative / PWM-Fan-controller

An ESPHome Automatic PWM Fan controller with Alarm
MIT License
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Used MOSFET not for 3.3V logic level #4

Closed lethuer closed 1 year ago

lethuer commented 1 year ago

I recognised the used mosfet "STP16NF06L" does not switch reliable with Uds = 12V and Ugs = 3.3V which is delivered by D1 Mini. For 3.3V logic level a better choice could be IRLZ44N for example.

3ative commented 1 year ago

Looking at the Datasheets: The STP16NF06L has a Vgs(th) of 1V to 2.5v The IRLZ44N has a a Vgs(th) of 1V to 2V So both would work.

I chose the STP16NF06L as the unit price was cheaper.

lethuer commented 1 year ago

From the datasheet I would agree but STP16NF06L doesn't work for me at Ugs 3.3V, with 5V the mosfet switched on. I just tried it on the bench and wanted to point this out.

Another thread with some interesting information about logic level mosfets: Using MOSFETS with TTL levels (5 Volt and 3.3 Volt) "Another thing to beware of in datasheets is Vthresh (threshhold voltage). This is not the gate voltage to turn the device on, its the gate voltage at which it switches fully off (less than a few uA of current, typically). If Vthresh is given as 2..4V range, it cannot be a logic level MOSFET (Vthresh is usually 0.5 to 1V for logic-level MOSFETs)."

3ative commented 1 year ago

Are you sure you are using the "L" or "Logic Level" version, I.E. STP16NF06L and not STP16NF06 ?

As stated in the link you posted: "... logic level MOSFET (Vthresh is usually 0.5 to 1V for logic-level MOSFETs)." and the ones I spec here have a Vthresh 1V to 2.5V

lethuer commented 1 year ago

Yes I am...