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sphyics

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Hi all,

Ckt diagram for ntype JFET

The values are as follows

V2 = -10 V , V1 = +10V

R1 = 1M ohm

R2 = 10 k ohm

IDss (drain current with shorted gate condition [tex]^{}_{}Vgs[/tex]= 10mA

Vp = 4v {Vp= pinch off voltage}

http://img233.imageshack.us/img233/4007/19716664vu3.png

https://www.physicsforums.com/newattachment.php?do=manageattach&p=1600867

Vgg = V2 = -10 V

Vdd = V1 = +10V

From kirchhoffs law

(-Vgg ) – (Ig)* (Rg) – Vgs = 0 since (Ig ~= 0)

Vgs = (-Vgg) ------------------------------------------------------- ***********

Id = Idss( 1-(Vgs /Vp)^2

Id = 22.5 mA

Vdd – (Id)*(Rd) – Vds = 0

Vds = Vdd – (Id)*(Rd)

Getting an absurd answer for Vds (= -215V)

aim was to obtain Vds then Vds = Vd – Vs; as Vs = 0, Vds = Vd

Can anyone help me out by pointing my fault in analysis. Or is there any other method to solve for Vd .

Ckt diagram for ntype JFET

The values are as follows

V2 = -10 V , V1 = +10V

R1 = 1M ohm

R2 = 10 k ohm

IDss (drain current with shorted gate condition [tex]^{}_{}Vgs[/tex]= 10mA

Vp = 4v {Vp= pinch off voltage}

__To find drain voltage Vd =?__http://img233.imageshack.us/img233/4007/19716664vu3.png

https://www.physicsforums.com/newattachment.php?do=manageattach&p=1600867

__///////// SOLVED //////__**For gate source loop**Vgg = V2 = -10 V

Vdd = V1 = +10V

From kirchhoffs law

(-Vgg ) – (Ig)* (Rg) – Vgs = 0 since (Ig ~= 0)

Vgs = (-Vgg) ------------------------------------------------------- ***********

__By Shockley’s equation__Id = Idss( 1-(Vgs /Vp)^2

Id = 22.5 mA

__For drain source loop__Vdd – (Id)*(Rd) – Vds = 0

Vds = Vdd – (Id)*(Rd)

Getting an absurd answer for Vds (= -215V)

aim was to obtain Vds then Vds = Vd – Vs; as Vs = 0, Vds = Vd

Can anyone help me out by pointing my fault in analysis. Or is there any other method to solve for Vd .

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