- #1

beyondlight

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## Homework Statement

Calculate Rs so that the draincurrent ID = 4 mA. Vad does the gain A become? uo/ui? For the transistor:

k = 3 mA/V^2

Vt = -2 V

also:

R1 = 50 k ohm

Rd = 2.2 k ohm

C = infinity for signalfrequencies

image of circuit:

http://sv.tinypic.com/view.php?pic=9pyq9z&s=8#.VSbHQfl_vxM

## Homework Equations

[itex]i_{ds} = \frac{1}{2}k(v_{gs} - V_{t})^{2} [/itex] (1)

## The Attempt at a Solution

[itex]I_{D} = 4 mA [/itex] (2)

[itex]v_{d} = E - R_{D}\cdot I_{D} [/itex] (3)

[itex]v_{s} = R_{S}\cdot I_{D} [/itex] (4)

[itex]v_{ds} = ? [/itex]

From equation 1 we can get v_gs, that is the voltage between gate and source. But I still don't know how to get RS since I don't know u_in or v_ds.