MOSFET can be used as a?

By K Balaji|Updated : January 19th, 2023

MOSFET can be used as a Voltage Controlled capacitor. The gate and channel are separated by a thin layer of SiO2. Therefore, they form a capacitance that varies along with gate voltage. Here, MOSFET acts as a MOS Capacitor. It is controlled by the input gate to source voltage and hence, acts like a voltage-controlled variable capacitor.

Functional Region of MOSFET

The full form of MOSFET is Metal Oxide Semiconductor Field Effect Transistor. If a MOSFET's gate and drain are shorted, it can function as a small-signal resistor. When the Drain, Source, and bulk (body) of a MOSFET are shorted, this acts as one capacitor plate, and the Gate acts as another capacitor plate. The three main functional regions of a MOSFET are as follows:

  • Cut-off Region: The MOSFET is regarded as being in its "OFF" state when it is in the cut-off region. This means that no current passes through it when it is turned OFF.
  • Saturation Region: Saturation is the state where the MOSFET's current flow is constant. It acts as a closed switch in this area, enabling current to flow freely.
  • Linear/Ohmic Region: Increasing the voltage across the drain and source also increases the current flowing through the MOSFET in the linear/ohmic zone.

The MOSFET is considered the basic building block and the most frequently manufactured device. It is also the most common semiconductor device in both analogue and digital circuits.

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  • For the purpose of voltage-controlled capacitors, MOSFET can be used. MOSFET is an electronic device that is used to switch or amplify voltages in circuits. It is a voltage-controlled device where three terminals are used to construct it. MOSFET is also a common power device and semiconductor.

  • Automotive electronics frequently employ power MOSFETs, particularly as switching components in electronic control modules and as power converters in contemporary electric automobiles. A wide range of applications also utilizes the hybrid MOS-bipolar insulated-gate bipolar transistor (IGBT).

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