Final answer:
A MOSFET is a transistor that can act as a switch or an amplifier. It controls the flow of current by applying a voltage at the gate. By applying different voltages, the MOSFET can be turned on or off, allowing or blocking the flow of current.
Step-by-step explanation:
A MOSFET, or Metal-Oxide-Semiconductor Field-Effect Transistor, is a type of transistor that is commonly used in electronic devices. It consists of a gate, a source, and a drain. The basic working principle of a MOSFET involves the control of the flow of current through the transistor by applying a voltage at the gate. Depending on the applied voltage, the MOSFET can be in either an on-state or an off-state, allowing it to act as a switch or an amplifier in a circuit.
When a positive voltage is applied at the gate of an n-channel MOSFET, it creates an electric field that attracts negatively charged electrons from the source towards the channel, forming a conductive channel between the source and the drain. This allows current to flow through the transistor. On the other hand, when a negative voltage is applied at the gate, it repels the electrons away from the channel, blocking the flow of current.
Similarly, in a p-channel MOSFET, the polarity of the voltages is reversed. Applying a negative voltage at the gate attracts positively charged holes from the source towards the channel, creating a conductive path for current. Applying a positive voltage repels the holes away, preventing current from flowing.