Integrator
* created by AmiSPICEed!
V0 1 2 DC 5V
R0 0 2 1M
R2 1 0 1M
X0 0 4 1 2 3 uA741
C1 4 3 1uF
R1 5 4 10K
V1 5 0 PWL( 0s 0v 10ms 0V 20ms 1V 30ms 1V 31ms 0V 50ms 0V 60ms -1V 70ms -1V 71ms 0V 100ms 0V)
R3 0 3 10K
.subckt uA741 1 2 3 4 5
C1 11 12 8.661E-12
C2 6 7 30.00E-12
Dc 5 53 dx
De 54 5 dx
Dlp 90 91 dx
Dln 92 90 dx
Dp 4 3 dx
Bgnd 99 0 V=(0.5*V(3,0))+(0.5*V(4,0))
Bb 7 99 I=(10.61E6*I(Vb))+(10E6*(-I(Vc)+I(Ve)+I(Vlp)-I(Vln)))
Ga 6 0 11 12 188.5E-6
Gcm 0 6 10 99 5.961E-9
Iee 10 4 DC 15.16E-6
Hlim 90 0 Vlim 1K
Q1 11 2 13 qx
Q2 12 1 14 qx
R2 6 9 100.0E3
Rc1 3 11 5.305E3
Rc2 3 12 5.305E3
Re1 13 10 1.836E3
Re2 14 10 1.836E3
Ree 10 99 13.19E6
Ro1 8 5 50
Ro2 7 99 100
Rp 3 4 18.16E3
Vb 9 0 DC 0
Vc 3 53 DC 1
Ve 54 4 DC 1
Vlim 7 8 DC 0
Vlp 91 0 DC 40
Vln  0 92 DC 40
.Model dx D(Is=800.0E-18 Rs=1)
.Model qx NPN(Is=800.0E-18 Bf=93.75)
.ends
.IC V(3)=0V
.TRAN 1ms 100ms 0ns 
.save V(3) V(5)
.END