# Question 4.5: In the amplifier of Fig. 4-9(a), VDD = 15 V, RL = 3 kΩ, and ......

In the amplifier of Fig. 4-9(a), $V_{DD} = 15 \text{V}, R_L = 3 kΩ,$ and $R_F = 50 MΩ$.    If the MOSFET drain characteristics are given by Fig. 4-9(b), determine the values of the quiescent quantities.

Step-by-Step
The 'Blue Check Mark' means that this solution was answered by an expert.

The dc load line is constructed on Fig. 4-9(b) with $v_{DS}$ intercept of $V_{DD} = 15 \text{V}$ and $i_D$ intercept of $V_{DD}/R_L = 5 \text{mA}$.    With gate current negligible (see Section 4.3), no voltage appears across $R_F$, and so $V_{GS} = V_{DS}$.    The drain-feedback bias line of Fig. 4-9(b) is the locus of all points for which $V_{GS} = V_{DS}$.    Since the $Q$ point must lie on both the dc load line and the drain-feedback bias line, their intersection is the $Q$ point.    From Fig. 4-9(b), $I_{DQ} ≈ 2.65 \text{mA}$ and $V_{DSQ} = V_{GSQ} ≈ 6.90 \text{V}$.

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...