JFET carrier flow directions: In a junction field-effect transistor, do charge carriers move from source to drain in a p-channel device and from drain to source in an n-channel device?

Introduction / Context:Understanding current and carrier flow directions in junction field-effect transistors (JFETs) is foundational in electronics. The statement mixes up conventional current with actual charge-carrier motion for p-channel and n-channel JFETs. Clarifying this distinction helps prevent sign and polarity mistakes when biasing or analyzing JFET circuits.

Given Data / Assumptions:

• N-channel JFET uses electrons as majority carriers; p-channel JFET uses holes.
• Standard terminal naming: gate (G), drain (D), source (S).
• Biasing is such that the gate-channel junctions remain reverse-biased in normal operation.
• Conventional current direction is defined as positive charge flow.

Concept / Approach:In an n-channel JFET, conventional drain current (ID) flows from drain to source, but electrons (negative carriers) physically move from source to drain—opposite to conventional current. In a p-channel JFET, holes are the carriers and move from source to drain; conventional current also flows from source to drain. The statement claims carriers move source→drain in p-channel (true) and drain→source in n-channel (false; electrons move source→drain).

Step-by-Step Solution:

Verification / Alternative check:Use the sign of VDS and the established symbol conventions: for an n-channel device, typical operation has the drain at a higher potential than the source. Electrons flow toward the drain terminal internally from the source side, confirming source→drain carrier motion for electrons.

Why Other Options Are Wrong:

Common Pitfalls:Confusing conventional current with electron flow; assuming both channel types share the same carrier direction; forgetting that diagrams typically show current arrows, not carrier drift direction.

Final Answer:Incorrect