Page 31 - ebook PdP FET

TABLE OF CONTENTS
SUMMARY

VGS= 0V
When the gate-to-source voltage is zero, the depletion region
is narrow.

The channel offers low resistance to the current flow between CHAPTER 4
the source and the drain terminals.
This is called the "pinch-off" condition, and the JFET is said to
be in saturation.
JFET produce constant saturation current, IDSS

VGS more negative
When the gate-to-source voltage decreases, the depletion
region around the channel between the source and drain CHAPTER 3
increases in width.
This reduces the effective channel width, which in turn,

decreases the conductivity of the channel.
As a result, the drain current decreases, and the JFET becomes
more resistive.
When it reach value of VGS (off), channel is completely cut-
off and the drain current becomes zero.

VGS less negative CHAPTER 2
When the gate-to-source voltage increases, the depletion

region around the channel between the source and drain
decreases in width.
This increases the effective channel width, which in turn,
increases the conductivity of the channel.
As a result, the drain current also increases, and the JFET
CHAPTER 1
becomes less resistive.

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