Consider the JFET amplifier in the Figure below with transistor parameters loss = 6 mA, VGS (OFF) = -3 V and VA = 100 V. Let VDD = 10 V. a) Determine RD and VGs such that lp = 4 mA and VDs = 6 V. b) Determine gm and ro. c) Determine the small-signal voltage gain Av = Vo/Vi. VDD Vj + VGS + H + VGS o www + UDS VO

Figure 4 shows a differential amplifier where the input voltage is Vin = Vil the output voltage is Vout - Vi2 and %3D Vo- (a) What kind of amplifier is it? Draw the small equivalent circuit and calculate the differential voltage gain G, in the case of balanced input and unbalanced output. For the calculation, consider the output resistances roi of the two transistors as open circuits (negligible current flowing in them). Show the detail of the calculation and state any assumption. (b) (c) What is Gv if you include the output resistances roi in the analysis? For the balanced input and identical transistors, the current variation in M1 and M2 are equal and opposite: i1 = -i2 (the current flowing in Rs is i- 0). V DD Rp1 Rp2 VinLM, M2 V2 V'ss =0 V Figure 4

The amplifier configuration shown in figure below is a a) common emitter b) common collector c) common base d) base follower configuration, where the is at ac ground, and the ac output voltage a) collector B) emitter C) capacitor D) base with the input. A) amplified and 180deg out of phase B) almost equal and 180degree out of phase C) almost equal and in phase D) amplified and in phase

9. State the relationships of the small signal hybrid- π parameters gm & rn to the transistor dc quiescent values. Draw the small signal model of the adjacent BJT amplifier circuit: Rs=0.5 KQ ww HH Cc Vcc= 10 V R₁ = • 56 ΚΩ www 3 R₂ = 12.2 kQ2 Rc=2kQ - VO RE=0.4 KQ