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.
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.
Can a MOSFET be a ground referenced load?
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. However, your gate drive will need to be reversed and will need to be close to your higher voltage to turn the load off.
When does a channel exist in a MOSFET?
When a channel exists in a MOSFET, current can flow from drain to source or from source to drain – it’s a function of how the device is connected in the circuit.
Where does the diode point in a MOSFET?
To clarify a bit what others have already said, a MOSFET has a internal diode that points from source to drain in N channel devices and drain to source in P channel devices. This is not something added deliberately by the manufacturer, but is a byproduct of the way MOSFETs are made.