Operational Amplifiers

12 Operational Amplifiers

Figure 12.2 A voltage amplifier R S + + v ( t ) R v ( t ) Gain, A _ S L L – Source Amplifier Load

Figure 12.3 Simple voltage amplifier model R R S out + + Av v in S + + v R v _ _ in L R L in – –

Positive power supply i in + V + v S Inverting input + R out R v in in + + Output _ – A v V ( OL ) in Noninverting input v – v V out S – Negative – power supply Simplified circuit symbol Op-amp model V S Offset null No connection 1 8 Inverting input V S 2 7 Inverting Noninverting input Output input in – 3 6 Output Noninverting V Offset null S input in + 4 5 Integrated circuit operational amplifier (IC op-amp) V S Figure 12.4 Operational amplifier model symbols, and circuit diagram + – + + – – IC op-amp diagram

Figure 12.5 Inverting amplifier R F i F R – v S – i i in S + + + + v _ v S v out –

Figure 12.7 Summing amplifier R F R S 1 i F + i 1 _ v S 1 v out R S 2 + i 2 _ v S 2 R S N + i N _ v S N

Figure 12.8 Noninverting amplifier R F i i R F in S – v – i S v + + + R i in v + out v _ S –

Figure 12.9 Voltage follower – + i + in v + out v _ in –

Figure 12.10 Differential amplifier R 2 i 2 R 1 – + i 1 + + v v out R _ 1 1 + – v R _ 2 2

Figure 12.14 Instrumentation amplifier v R R 1 F R 2 R 1 V out R 2 v R 2 R F

Figure 12.20 Op-amp circuits employing complex impedances Z F I F Z – S + + I + S V ~ out V S – – Inverting Z F I F – Z S + I + S V out + – V ~ S – Noninverting

Figure 12.21 Active low-pass filter Z F C F R F R S – + + + V V out _ S –

Figure 12.24 Active high-pass filter R F Z S R C S S – + + V out + V _ – S

Figure 12.26 Active band-pass filter R F C F R C S S – + + + V V _ out S –

Figure 12.27 Normalized response of active band-pass filter

Operational Amplifiers