# Question 4.6: The drain-feedback biased amplifier of Fig. 4-9(a) has the c......

The drain-feedback biased amplifier of Fig. 4-9(a) has the circuit element values of Example 4.5 except that the MOSFET is characterized by the parameter values of Example 4.4. Apply SPICE methods to determine the quiescent values.

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The netlist code below describes the circuit.

 Ex4_6.CIR – Drain-feedback bias vi       1 0 0V ; Value inconsequential CC     1 2 100uF; Value inconsequential RF     2 3 50MEGohm RL     3 4 3kohm VDD 4 0 15V M 3   2 0 0 NMOSG .MODEL NMOSG NMOS (Vto=4V Kp=0.0008ApVsq + Rd=1ohm Rg=1kohm) .DC VDD 15V 15V 1V .PRINT DC ID(M) V(2) V(3) .PROBE .END

Execute 〈Ex4_6.CIR〉 and poll the output file to find $I_{DQ} = ID(M) = 2.79 \text{mA}, V_{DSQ} = V(3) = V_{GSQ} = V(2) = 6.64 \text{V}$.

Question: 4.SP.19

## Identical JFETs characterized by iG = 0,  IDSS = 10 mA, and Vp0 = 4 V are connected as shown in Fig. 4-24. Let R_D = 1 kΩ, RS = 2 kΩ, and VDD = 15 V, and find (a) VGSQ1, (b) IDQ2, (c) VGSQ2, (d) VDSQ1, and (e) VDSQ2. ...

(a)   With negligible gate current, (4.2) gives [l...
Question: 4.SP.18

## For the series-connected identical JFETs of Fig. 4-23, IDSS = 8 mA and Vp0 = 4 V. If VDD = 15 V, RD = 5 kΩ, RS = 2 kΩ, and RG = 1 MΩ, find (a) VDSQ1, (b) IDQ1, (c) VGSQ1, (d) VGSQ2, and (e) VDSQ2. ...

(a) By KVL, V_{GSQ1} = V_{GSQ2} + V_{DSQ1}[...
Question: 4.SP.17

## The differential amplifier of Fig. 4-22 includes identical JFETs with IDSS = 10 mA and Vp0 = 4 V. Let VDD = 15 V, VSS = 5 V, and RS = 3 kΩ. If the JFETs are described by (4.2), find the value of RD required to bias the amplifier such that VDSQ1 = VDSQ2 = 7 V. ...

By symmetry, $I_{DQ1} = I_{DQ2}$. KCL...
Question: 4.SP.16

## Find the equivalent of the two identical n-channel JFETs connected in parallel in Fig. 4-21. ...

Assume the devices are described by (4.2); then [l...
Question: 4.SP.25

## The amplifier of Example 4.7 has plate current iP = IP + ip = 8 + cos ωt mA  Determine (a) the power delivered by the plate supply voltage VPP, (b) the average power delivered to the load RL, and (c) the average power dissipated by the plate of the triode. (d) If the tube has a plate rating of 2 W ...

(a)   The power supplied by the source V_{P...
Question: 4.SP.20

## Fixed bias can also be utilized for the enhancement-mode MOSFET, as is illustrated by the circuit of Fig. 4-25. The MOSFET is described by the drain characteristic of Fig. 4-9. Let R1 = 60 kΩ, R2 = 40 kΩ, RD = 3 kΩ, RL = 1 kΩ, VDD = 15 V, and CC → ∞. (a) Find VGSQ. (b) Graphically determine VDSQ ...

(a)  Assume $i_G = 0$. Then, by (4.3)...
Question: 4.SP.13

## A p-channel MOSFET operating in the enhancement mode is characterized by VT = -3 V and IDQ = -8 mA when VGSQ = -4.5 V. Find (a) VGSQ if IDQ = -16 mA and (b) IDQ if VGSQ = -5 V. ...

(a)   Using the given data in (4.6) leads to [late...
Question: 4.SP.12

## For the n-channel enhancement-mode MOSFET of Fig. 4-18, gate current is negligible, IDon = 10 mA, and VT = 4 V. If RS = 0, R1 = 50 kΩ, VDD = 15 V, VGSQ = 3 V, and VDSQ = 9 V, determine the values of (a) R1 and (b) RD. ...

(a)    Since i_G = 0, V_{GSQ} = V_{GG}[/lat...
Question: 4.SP.11

## The n-channel enhancement-mode MOSFET of Fig. 4-18 is characterized by VT = 4 V and IDon = 10 mA. Assume negligible gate current, R1 = 50 kΩ, R2 = 0.4 MΩ, RS = 0, RD = 2 kΩ, and VDD = 15 V. Find (a) VGSQ, (b) IDQ, and (c) VDSQ. ...

(a)    Solving (4.2) for $v_{GS}$ and...