Introductionto

Electronic Circuit DesignRichard R. Spencer

Mohammed S. Ghausi

Figure 10-1 Block diagram of a negative-feedback amplifier.

(10.1)

(10.2)

(10.3)

Figure 10-2 (a) The unilateral two-port model of an amplifier and (b) the same amplifier with negative feedback applied.

Figure A10-1 The four feedback topologies; (a) series-shunt, (b) series-series, (c) shunt-shunt, and (d) shunt-series.

Figure 10-12 A series-shunt feedback amplifier with feedback network loading included.

Figure 10-13 (a) The feedback amplifier of Figure 10-12 with the two-port identified and (b) the simplified equivalent feedback amplifier.

Figure 10-18 (a) The series-shunt amplifier with nonideal source and load added. (b) The amplifier after absorbing the feedback network loading into the primed network.

Figure 10-19 Determining the input resistance with feedback of the practical series-shunt amplifier.

Figure 10-20 Circuit for finding the output resistance of the series-shunt feedback amplifier of Figure 10-18(b).

Figure 10-30 (a) A series-series negative feedback amplifier and (b) the feedback network loading absorbed into the forward amplifier to form the primed network.

Figure 10-37 (a) A practical shunt-shunt amplifier using two-port models. (b) The model after absorbing feedback network loading into the forward amplifier.

Figure 10-43 (a) A shunt-series amplifier. (b) The primed network.

Figure 10-58 (a) A possible transfer characteristic for the forward amplifier shown below. (b) The resulting output if the loop gain is slightly greater than one at the frequency 180, and an oscillation is started at t = 0.

Figure 10-59 The Bode plot for a feedback amplifier with a(j) given by (10.244), as shown below, and b = -50 dB.

Figure 10-60 (a) An RC low-pass filter and (b) the step response.

Figure 10-61 (a) The positions of the poles of the second-order system described by (10.251), which is shown below, as a function of . (b) Sample step responses.

Figure 10-73 (a) Lag-lead compensation. (b) Lead-lag compensation.

Figure 10-74 A positive feedback loop.

Figure 10-75 An alternate view of a positive feedback loop for an oscillator.

Figure 10-76 A Wien-Bridge oscillator.

Figure 10-81 A phase shift oscillator.

Figure 10-84 A Colpitts oscillator.

Figure 10-89 A Colpitts crystal oscillator.

Figure 10-90 (a) The block diagram of a relaxation oscillator and (b) the resulting waveforms.

Figure 10-91 A relaxation oscillator using RC charging.

Figure 10-92 The block diagram of a 555 Timer IC.

Figure 10-93 The 555 Timer connected as a one shot.

Figure 10-94 The waveforms for the one shot of Figure 10-93.

Figure 10-95 The 555 connected as an oscillator.

Figure 10-96 The waveforms for the oscillator in Figure 10-95.