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Difficulty: HardTransistors

Unlike current-driven bipolar devices, an enhancement-mode metal-oxide-semiconductor field-effect transistor (MOSFET) conducts significant current between its drain and source terminals when its gate-to-source voltage is zero.

Answer: Answer

Answer

False. Enhancement-mode MOSFETs are normally-off devices that require a gate-to-source voltage exceeding the threshold voltage to establish a channel and conduct current.
The evaluation 'False' is correct because enhancement-mode MOSFETs are normally-off solid-state devices. Without an applied gate-to-source voltage exceeding the device's threshold voltage (VthV_{th}), the channel between the drain and source remains non-conductive, preventing drain current from flowing.

Step-by-Step Solution

1
Identify the component classification and operating archetype specified in the statement.
The statement specifies an enhancement-mode metal-oxide-semiconductor field-effect transistor (MOSFET).
Different transistor families (bipolar vs. field-effect) and operational modes (enhancement vs. depletion) exhibit distinct default conduction states.
2
Analyze the channel status of an enhancement-mode device at zero gate-to-source voltage (VGS=0 VV_{GS} = 0\text{ V}).
At VGS=0 VV_{GS} = 0\text{ V}, no conductive channel connects the drain and source regions across the substrate, resulting in an open circuit where drain current (IDI_D) is approximately zero.
Enhancement-mode devices are manufactured without a pre-formed channel and operate as normally-off switches.
3
Determine what electrical condition is required to initiate conduction.
An electric field created by applying a gate-to-source voltage greater than the threshold voltage (VGS>VthV_{GS} > V_{th}) is mandatory to enhance/induce a channel.
Because current does not flow at zero bias, the assertion that it conducts significant current at zero gate voltage is incorrect.

Key Concept

Default conduction state and threshold voltage mechanics of enhancement-mode field-effect transistors

Alternative Method

Recall the root word 'enhance': the channel must be actively enhanced (created) by gate voltage, meaning at zero gate voltage, no channel exists and no current flows.
Estimated Time:45s
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Topics

Transistors

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