A circuit as shown in Fig. 5.1 has V_CC= 15V, R₁= R₂= 0, R₃= 5k„¦, R_L= 2k„¦, V_CE(sat)= 0.2 V, and V_BE(on)= 0.7 V. All device areas are equal.

(a). Sketch the transfer characteristic from V_i to V_o.

(b). Repeat (a) if R_L = 10 k„¦.

(c). Sketch the waveform of V_o if a sinusoidal input voltage with an amplitude (zero to peak) of 10 V is applied at V_i in (a) and (b) above.

(d). Use SPICE to verify (a), (b), and (c) and also to determine second and third harmonic distortion in V_o for the conditions in (c).

Figure 5.1

+Vc_ Q1 V; I'e RL R3 Q2 Q3 R2 R1 -Vcc