dual gate MOSFET
The devices used in the above link is what is being discussed. You might notice they have no protection diodes. I keep hearing they do?
Any way. If you take a standard E-MOS and strap a 100k resistor from gate to drain you can put it in a circuit and build an amp with no further biasing required. It will "self regulated" at a point where the drain voltage "matches" the gate voltage required by the amp. In other words the drain voltage will be at supply as the power is applied. When the MOSFET conducts the drain voltage drops and the gate voltage follows until it reaches a balance point. Knowing this let's look inside the D-MOS.