THANK YOU.
This IRF3205 N-MOSFET transistor implementation has different parameters than in catalogue. I gradually applied the Gate-Source voltage and around 4V the Drain-Source resistance dropped to 38 mOhm. In other words Vgs(th) = 4V instead of 2V (catalogue value) and Rds(on) = 38 mOhm instead of 8 mOhm (catalogue value). In my opinion this IRF3205 N-MOSFET transistor implementation is not perfect, and should be used in applications where power efficiency is not critical, because it dissipates almost 5 times more power than catalogue transistor.