The Evolution and the History of Current Conveyors - Current Conveyors: Variants, Applications and Hardware Implementations - page 7

realizing the Chua family of new non-linear network elements, namely, the
mutators, rotators, scalars and reflectors with minimum possible number of
passive elements.
• 1971: Black et al. in [ 5 ] presented an integratable implementation of CCII using
ʼ

A749 IC chip (containing two operational amplifiers with uncommitted output
collectors) along with five additional transistors (obtained from an integrated
transistor array CA3046) to realize CCII+, which, with some more transistors
added, could also lead to a CCII .

• 1978: In [ 6 ], Bakhtiyar and Aronhime presented a CCII implementation using as
many as five op-amps.

• 1979: The first ever configuration for floating inductor simulation (parallel RL

type) employing the least possible number of active and passive component
namely, only one CCII

, a single capacitor and only two resistors, was intro-
duced by Senani [ 9 ]. This result was important in view of the fact that no such
circuit was known in the earlier literature using op-amps or any other kind of
devices known till then. In the same year, a circuit for floating series-RL type
lossy inductance simulation was also proposed by Singh in [ 10 ].
• 1980: A novel implementation of the CCs was introduced by Senani in [ 7 ] who
used an op-amp, an OTA and only one/two resistors to realize all the four
varieties of CCs namely, CCI+, CCI from the same

configuration. Huertas, in [ 8 ], came up with an entirely op-amp version of
Senani

, CCII+ and CCII

s circuit.
• 1981: In [ 11 ], Filanovsky and Stromsmoe introduced the Current-voltage Con-
veyor (CVC) with two versions called CVC1 and CVC2 which were shown to be
useful elements for the realization of controlled sources, negative impedance
converters and other active elements It was shown that the CVC could be
realized by the OA-OTA based synthesis as done previously for CC realization
by Senani in [ 7 ].
• 1982: Dostal and Pospisil [ 13 , 14 ] extended the idea of Current Conveyors to
define three novel types of Voltage Conveyors called VC1, VC2 and VC3. They
further demonstrated that the three-port immittance convertor is an useful
transformation building block leading to two basic types of convertors which
they chose to call summing voltage immittance convertor (SVIC) and summing
current immittance convertor (SCIC) which were capable of leading to, as
special cases, three varieties of Current Conveyors and three varieties of voltage
conveyors.

'

• 1984: In [ 15 ], Senani showed that the generalized current conveyor (character-

ized by the instantaneous terminal relations i y ¼ h 32 i x )

in conjunction with an active-RC network derived from a given grounded
immittance simulation network i.e. one-port with y 11 ¼

h 12 i x ,v x ¼ h 21 v y and i z ¼

y(s), can be used to
realize the same type of immittance function in floating form i.e. as a two-port
characterized by y 11 ¼ ky(s), k being a positive scale

factor, with several advantages over earlier methods of floating immittance
realization.

y 12 ¼ y 21 ¼ y 22 ¼