CH5 OPERATIONAL AMPLIFIERS
(op amp)
5.1 Operational amplifiers
1. Introduction
?An op amp is an active circuit element. ?The op amp is an electronic unit that behaves like a voltage-controlled voltage source
?Op amps are commercially available in Integrated Circuit packages.
BalanceInverting inputNoninverting inputU -U -12348765No connectionU +OutputBalance0t7U+0UotInverting input2Noninverting input 3U +-+t+Uo6Output0U-4150t2. circuit symbol
Ground
input
Noninvertinginput voltage ：u+Inverting input voltage：u-Output: uo
output
u+u-
+
+A-uo
abu++u-__+A+-o+uo_3. Main parameter
(1) A : voltage amplification factor
A=105～106，even more+
a①u0=Au+-=A(u+ -u-)
bu++u-__+A+-o+uo_②u+ :noninvertinginput voltage
u-:invertinginput voltage（a）whenu-= 0，uo=Au+（b）when u += 0，uo=-Au-
CH05-Operational Amplifiers
