Enhancement mode MOSFETs are commonly used as switches. Let's delve into the details to understand why this is the case.

What are Enhancement Mode MOSFETs?
Enhancement mode MOSFETs are a type of metal-oxide-semiconductor field-effect transistor (MOSFET) that requires a positive voltage at the gate terminal to activate the device. Without this positive voltage, the device remains in an off state.

Operation of Enhancement Mode MOSFETs
Enhancement mode MOSFETs operate by controlling the flow of current between the source and drain terminals using a voltage applied to the gate terminal. When a positive voltage is applied to the gate, it creates an electric field that attracts or repels charge carriers in the channel region, allowing current to flow between the source and drain. Conversely, when no voltage or a negative voltage is applied to the gate, the channel remains closed, and no current flows.

Why are Enhancement Mode MOSFETs used as Switches?
Enhancement mode MOSFETs have several characteristics that make them well-suited for use as switches:

1. High On/Off Ratio: Enhancement mode MOSFETs can achieve a high on/off ratio, meaning they can effectively switch between conducting and non-conducting states. This makes them ideal for applications where precise control over current flow is required.

2. Low Power Consumption: When an enhancement mode MOSFET is in the off state, it has very low power consumption. This makes it energy-efficient and suitable for battery-operated devices.

3. Fast Switching Speed: Enhancement mode MOSFETs can switch on and off rapidly, allowing them to handle high-frequency signals and fast switching applications.

4. Wide Range of Voltage and Current Levels: Enhancement mode MOSFETs are available in various voltage and current ratings, making them versatile for different applications.

5. Simple Control: The gate voltage controls the switching action of the MOSFET, making it easy to interface with digital logic circuits or microcontrollers.

Conclusion
Enhancement mode MOSFETs are commonly used as switches due to their high on/off ratio, low power consumption, fast switching speed, wide voltage and current range, and easy control. These characteristics make them suitable for a wide range of applications, including power electronics, motor control, and digital circuits.