Match Field-Effect Transistor (FET) parameters to typical order-of-magnitude values (corrected units): (A) gm for JFET, (B) rd for JFET, (C) rd for MOSFET, (D) gg for JFET — with: (1) 25 kΩ, (2) 0.01 S, (3) 0.5 MΩ, (4) 10^-8 S.

Introduction / Context:Designers often estimate FET small-signal parameters by order of magnitude. Typical room-temperature values help with quick checks before detailed datasheet review or SPICE extraction. The original options mixed units ambiguously (e.g., 'mW' for a conductance). Here, units are corrected for clarity.

Given Data / Assumptions:

• gm (transconductance) is measured in siemens (S).
• rd (drain resistance) is measured in ohms (Ω).
• gg (gate conductance) is extremely small (near leakage), in siemens (S).
• Typical magnitudes: gm for JFET in the mS to 10 mS range; rd for JFET on the order of tens of kΩ; rd for MOSFET (small-signal, triode-region excluded) can be hundreds of kΩ to mega-ohms; gg for JFET around 10^-8 S (or lower).

Concept / Approach:Map each parameter to a plausible magnitude used in hand calculations and conceptual exam problems.

Step-by-Step Solution:

Verification / Alternative check:Sanity check: gm * rd for JFET gives intrinsic gain order gmrd ≈ (10 mS)(25 kΩ) ≈ 250, a reasonable small-signal estimate. MOSFET's higher rd aligns with channel-length modulation effects.

Why Other Options Are Wrong:

• A-1, B-2, C-3, D-4: Assigns JFET gm to 25 kΩ (wrong unit and concept).
• A-4, B-2, C-3, D-1: Gives gm an unphysically tiny conductance and swaps resistances.
• A-2, B-3, C-1, D-4 (distractor): Misplaces which device typically has larger rd.

Common Pitfalls:

• Confusing resistance (Ω) with conductance (S); they are reciprocals.
• Using power units (W) by mistake for small-signal parameters.

Final Answer:A-2, B-1, C-3, D-4