Example 3.3 - Ideal Op-Amp Circuit with Variable Gain
*
* The ideal op-amp has infinite input resistance, infinite gain,
* and zero output resistance. The resistances can be represented
* in PSpice by open and short circuits. The infinite gain must be
* represented by a very large, but finite, number such as A=1E10.
*
.OPT NOPAGE NOBIAS ; Suppress printing of node volt calculation
;
Vin 1 0 DC 1 ; When Vin=1 then GAIN = Vout/Vin = Vout.
;
EAMP 3 0 0 2 1E10 ; 1E10 = gain approximation to ideal op-amp
; Voltage controlling the VCVS is + at node 0
R1 1 2 1K
R2 2 3 RFDBAK 1 ; 1=multiplier of model parameter given below
RL 3 0 4.7K
.MODEL RFDBAK RES(R=1k) ; Resistance model with parameter R=1k
.DC RES RFDBAK(R) 1k 10k 1k ; DC sweep of model parameter R from 1x1k
; to 10x1k in steps of 1x1k.
.PRINT DC V(1) V(3)
.PROBE V(1) V(3)
.END