I'm currently trying to find an N-channel MOSFET to act as a switch to be controlled by my Arduino, and I've come across two particular MOSFETS so far that seem like they would be a good fit to the application I am trying to do.
The first one is this one: https://components101.com/mosfets/irfz44n-datasheet-pinout-features
The second one is this one: https://www.infineon.com/cms/en/product/power/mosfet/12v-300v-n-channel-power-mosfet/irlz44n/.
For the first MOSFET, in that link it says that the MOSFET will turn on starting at 4V and won't fully turn on until it exceeds 10V, so its recommended to use the second MOSFET I've linked. I'm kinda new to this so I was wondering how do I know that the first MOSFET requires 10V to fully turn on? I looked at the datasheet and while I don't understand most of it, I did see the section labelled as Vgs(TH). The min voltage stated is 2V while the max voltage stated is 4V. Does the 2V not mean anything then? Why does the datasheet state 4V is that max Vgs(TH)? Looking at the absolute maximum ratings, it seems that Vgs should get nowhere near 20V, so how do I know that at 10V it will start to be fully on to use as a switch?
In the link to the first MOSFET, it also actually recommends using the second MOSFET I've linked if I want to use a microcontroller to control the transistor. They've come to that conclusion because the second MOSFET can be fully turned on using the 5V from an Arduino.