Suppose that each output channel of a computer’ssound card can be represented by a 1-V ac sourcein series with a 32-Ω resistor. Each channel ofthe amplifier in the external speakers has an inputresistance of 20 k , and must deliver 10 W intoan 8-Ω speaker. (a) What are the voltage gain, currentgain, and power gain required of the amplifier?(b) What would be a reasonable dc power supplyvoltage for this amplifier?

b) For correct operation as an ac amplifier a JFET must be correctly DC biased to establish an appropriate Q-point, i.e a positive voltage VDs between the drain and source terminals and a negative voltage VGs between the gate and drain terminals. Figure 2.1 shows a circuit that can achieve this requirement. Explain the role of each resistive element in this circuit. Vin RG1 Cin HT lin RG2 VG 3º Rs + VDD ¡VD Cout Figure 2.1 Vout Cs ¡out