Nonlinear Applications of CCs - Current Conveyors: Variants, Applications and Hardware Implementations - page 242

b

a

R

i L

i 0

R 1

+ + +

C 2 C 1

V C1 V 0

L

V C2

X

− − −

CCII+1 Z

Y

c

R 4

I L

Y

CCII+ Z Y

CCII+

R 3

Z

C

X

X

I 0

R L1

R L2

Y

X

Z

CCII+2 CCII+

Z

X
Y

Y CCII+

Z

X

R 2

Fig. 8.30 Chua ' s circuits and its CCII+ based implementations as proposed by Sanchez-Lopez
et al. (a) Chua ' s circuit (b) Chua ' s diode (c) Simulating inductance using CCII+ s [ 20 ]

In principle many different implementations of Chua s oscillator can be obtained

'

depending upon how one realizes the Chua s diode and the simulated inductor. A

'

Chua s diode implementation using two CCII+ and four resistors (analogous to the

one devised by Senani-Gupta in [ 24 ]) has been shown in Fig. 8.30b . On the other
hand a simulating inductance circuit using only CCII+ elements and requiring a
bare minimum of only three passive components namely two resistors and a
grounded capacitor is shown in Fig. 8.30c .
With all the CCII+ s realize from AD844 this circuit exhibits a double scroll
attractor for the following component values and bias voltages. CCII+1 biased with
+5 V and CCII+ 2 biased with 12 V; the values of resistors as R 1 ¼6.76 K ʩ ,
R 2 ¼

'

3.91 K ʩ ,R 3 ¼ 0.47 K ʩ ,R 4 ¼ 10 K ʩ ,RL 1 ¼ R L2 ¼ 3.6 K ʩ ,C ¼ 4.7 nF,

C 1 ¼ .

Elwakil and Kennedy in [ 14 ] demonstrated that three-phase sinusoidal oscillator
based on current conveyors can also be modified to become chaotic oscillator using
a circuit called diode-inductor composite. One such implementation is shown in
Fig. 8.31 . The basic circuit is essentially a cascade of three identical first order low
pass sections such that the diode-inductor composite has been inserted in series with
resistor R 4 . In principle the diode-inductor composite could have been inserted in
series with any of three resistors R 4 ,R 5 and R 6 . It may be noted that CCII

4.7 nF, C 2 ¼ 47 nF and R ¼ 2,771 ʩ

can be

realized from two CCII+ s.
The chaotic behavior of this circuit has been confirmed for the following set of
component values: C 1 ¼ C 2 ¼ C 3 ¼ C ¼ 50 pF, R 1 ¼ R 2 ¼ R 3 ¼ R ¼ 15 K ʩ ,

R 4 ¼ R 5 ¼ R 6 ¼ KR, K ¼ 1/3, L ¼ 100 mH, R x ¼ 1K ʩ ,R z ¼ 5K ʩ and the DC