JFET characteristic information: Do the gate-biased JFET characteristic curves explicitly involve the drain–source current ID (often written as I_D), including the special case IDSS at VGS = 0 V?

Difficulty: Easy

Correct Answer: Correct

Explanation:


Introduction / Context:
Characteristic curves are the primary visual tool for understanding JFET behavior. They plot relationships among drain–source current (ID), drain–source voltage (VDS), and gate–source voltage (VGS). Knowing that ID, including the noted parameter IDSS, is central to these curves helps with design and bias calculations.


Given Data / Assumptions:

  • ID is the controlled current through the channel.
  • Curves typically show ID vs VDS for several fixed VGS values.
  • IDSS is the maximum ID at VGS = 0 V in the saturation region.
  • Shockley equation relates ID to VGS in the transfer characteristic.


Concept / Approach:
The output characteristics display families of ID–VDS curves parameterized by VGS. The transfer characteristic shows ID versus VGS for a fixed VDS in the saturation region, highlighting IDSS at VGS = 0 V and the cutoff at VGS(OFF). Thus, drain current ID is explicitly part of all these presentations.


Step-by-Step Solution:

Identify the axes on the output characteristic: vertical is ID; horizontal is VDS.Observe parameter lines: each curve corresponds to a specific VGS.Note special markers: IDSS at VGS = 0 V; cutoff near ID ≈ 0 at VGS(OFF).Conclude: the curves explicitly include ID, validating the statement.


Verification / Alternative check:
Cross-check with any JFET datasheet: the characteristic graphs always include ID either as the graphed variable (output characteristic) or as the dependent variable of VGS (transfer characteristic).


Why Other Options Are Wrong:

Incorrect: ignores what is plotted.Only VDS: current is essential on the other axis.Gate current plotted: gate current is negligible and not the focus.Only VGS(OFF): cutoff is a point on the ID curve, not the entirety of the data.


Common Pitfalls:
Confusing IDSS with IDS (notation variations); overlooking the required region (saturation vs ohmic) for applying specific equations; reading curves at the wrong VGS line.


Final Answer:
Correct

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