The term “NMOS” refers to the fact that the channel is built based on a N-doped region of silicon (excess of electrons) on top of a P-doped substrate (excess of holes). The current can be blocked by applying a negative voltage to the gate, that by field effect, will push electrons and attract holes. This means that a current can pass through the MOSFET with no voltage applied to the gate. The term “depletion” here refers to the fact that a physical channel is linking the drain branch to the source branch.
In the first figure below, the structure of a MOSFET is presented : fig 1 : Depletion NMOS structureįirst of all, let’s define the meaning of “depletion” and NMOS terms. In a MOSFET the command branch is named the Gate and it controls the current flow between the Source and the Drain. In a BJT, the Base act as the command signal to control the current flow between the Emitter and the Collector. There are however other types of transistors that can be used to build an amplifier architecture and in this tutorial, we will focus on one of them : the MOSFET (Metal Oxide Semiconductor Field Effect Transistor).
We have already seen in detail that a signal amplifier can be made with a Bipolar Junction Transistor (BJT).
0 kommentar(er)
