Do MOSFETs have polarity?
So the mosfet can only block current flow in one direction. The problem is internal diode, which will always conduct in reverse direction with 0.7V drop, so when you will switch MOSFET ON you will lower that drop down to 0V and that’s it.
How we decide the source and drain terminal in MOSFET?
Theoretically, the drain and source can be swapped, and when you do this, the source becomes the drain and the drain becomes the source. For an N-MOSFET, the source is the lower potential, and the drain is the higher potential.
How is the source and drain polarity of a MOSFET different?
This will be a mirror-image of the circuit you describe, ie with the source connected to the higher voltage and the drain connected to 0V via the load. However, your gate drive will need to be reversed and will need to be close to your higher voltage to turn the load off. A mosfet is really a four terminal device. Drain, source, gate and body.
What should the drain voltage of a MOSFET be?
Drain to source voltage of the MOSFET needs to be higher than the circuit voltage. If a circuit requires a maximum of 30V, a MOSFET with a drain to source voltage of 50V is required for safe operations. Always choose this parameter larger than the actual required.
What’s the difference between VGs and MOSFET drain?
Well, the gate is still being controlled by a voltage that is switched between 0v and 10v, but the source terminal is at 12v! So, Vgs will be -2v or -12v, and the MOSFET will never be able to get turned on. The voltage on the gate needs to always be referenced to the source terminal. If you forget to do that, you will wind up having problems.
How is the gate lowered in a p channel MOSFET?
To turn it on, the gate is lowered by 12-15V with respect to the source for most normal MOSFETs. If you want a ground-referenced load, you can use a P channel MOSFET. This will be a mirror-image of the circuit you describe, ie with the source connected to the higher voltage and the drain connected to 0V via the load.