An n-channel JFET has $${I_{{\text{DSS}}}} = 2\,{\text{mA}}$$ and Vp = -4 v. Its transconductance gm = in (mA/V) for an applied gate to source voltage VGS = -2 v is
A. 0.25
B. 0.5
C. 0.75
D. 1
Answer: Option B
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The action of JFET in its equivalent circuit can best be represented as a
A. Current controlled Current source
B. Current controlled voltage source
C. Voltage controlled voltage source
D. Voltage controlled current source
In a p+n junction diode under reverse bias, the magnitude of electric field is maximum at
A. The edge of the depletion region on the p-side
B. The edge of the depletion region on the n-side
C. The p+n junction
D. The center of the depletion region on the n-side
To prevent a DC return between source and load, it is necessary to use
A. Resistor between source and load
B. Inductor between source and load
C. Capacitor between source and load
D. Either A or B
gm = go(1-vgs/vp)
go = 2 idss/|vp|
= 2*0.002/4 = 0.001
gm = 0.001(1- (-2/-4))
=0.005 = 0.5mA/V
n channel JFET
𝑰𝑫𝑺 = 𝟐 𝒎𝑨
𝑽𝑫𝑺 = −𝟐 𝑽
The expression for gm is given as
𝒈𝒎 =
𝟐 𝑰𝑫𝑺𝑺
|𝑽𝑷|
[𝟏 −
𝑽𝑮𝑺
𝑽𝑷
]
𝒈𝒎 =
𝟐 × 𝟐 × 𝟏𝟎−𝟑
|−𝟒|
[𝟏 −
(−𝟐)
(−𝟒)
]
= 𝟎. 𝟓 𝒎𝑨/𝑽
Option (b)
I'd=Idss (1-Vgs/Vp)2
Id=1/2ma
Gm=I'd/Vgs
Gm=1/4
I'd=Idss (1-Vgs/Vp)2
Id=1/2ma
Gm=I'd/Vgs
Gm=1/4
Id= Idss(1 - Vgs/Vp)2 = 0.5mA
Ans should be 0.75.
Can you please provide the solution