Which statement describes a MOSFET?

Which statement describes a MOSFET?

• A. Low Input Impedance
• B. High Current Handling
• C. Slow Switching
• D. High Input Impedance, Fast Switching

Answer: (D)

A MOSFET is a voltage-controlled device with an insulated gate, so it presents a very high input impedance. Because almost no gate current flows, you can drive the gate with a small control voltage without loading the previous stage. That same insulated gate also allows fast switching, since turning the channel on or off is a voltage-driven action that relies on the formation or collapse of the conductive channel rather than injecting carriers into the base. So the combination of high input impedance and fast switching best describes a MOSFET. While some MOSFETs can handle large currents, and switching speeds can vary with device design, those traits aren’t the defining feature in the same way as the gate’s high impedance and rapid switching behavior.

A MOSFET is a voltage-controlled device with an insulated gate, so it presents a very high input impedance. Because almost no gate current flows, you can drive the gate with a small control voltage without loading the previous stage. That same insulated gate also allows fast switching, since turning the channel on or off is a voltage-driven action that relies on the formation or collapse of the conductive channel rather than injecting carriers into the base. So the combination of high input impedance and fast switching best describes a MOSFET. While some MOSFETs can handle large currents, and switching speeds can vary with device design, those traits aren’t the defining feature in the same way as the gate’s high impedance and rapid switching behavior.