# what is the relation of VGS on P and N channel mosfet

I'm a little bit confused on the Vgs(voltage-gate-source) of a mosfet...from what i understand so far the Vgs is simply the potential difference of the voltage applied from gate to source...

FOR EXAMPLE: using a p-channel mosfet assume that Vg=10 volts and my Vs=18 volts so i get a VGS= -8

using a n-channel mosfet assume that Vg=10 volts and my Vs=0 (vs is always 0 since the source is at the ground level) so i get a VGS= 10

i hope someone will clear this confusion of mine...TIA

• What is your confusion? Apr 14, 2018 at 10:39
• im confused if all the things i said was right i dont know if those are right Apr 14, 2018 at 10:40
• im sorry im just new to this electronics stuff Apr 14, 2018 at 10:41
• Yes you are correct. Vgs = Vg-Vs. For both n and p channel MOSFETs. Apr 14, 2018 at 10:45
• Yes you are correct. N channel FETs are usually easier to understand, I still have to stop and think about the polarity of P channel FETs too. Sometimes the negative sign is omitted in P channels, and simply written as the absolute value, |Vgs| = 8 V. However, in this case you do have to double check that the gate is indeed negative when compared to the source.
– A.S.
Apr 14, 2018 at 10:47