The Evolution and the History of Current Conveyors - Current Conveyors: Variants, Applications and Hardware Implementations - page 8

• 1984: Whereas a number of ideal floating FDNR circuits were reported by a
number of authors all of which employed three Current Conveyors two capac-
itors and their resistors, Senani demonstrated for the first time that the same
element could be realized by using no more than two Current Conveyors (both
CCII ) along with two capacitors and three resistors without requiring any

component-matching condition(s) [ 16 ].
• 1986: In [ 17 ], Senani proposed a family of three two-CC-five-passive-elements
based floating generalized positive impedance convertors/invertors which could
realize floating lossless inductor, floating frequency-dependent-negative-resis-
tance (FDNR) and floating frequency-dependent negative conductance (FDNC)-
all from the same configuration without requiring any component- matching
conditions.
• 1989: Two modified Current Conveyors were introduced by Pal in [ 21 ] out of
which the first one had complementary Z outputs whereas the second one could
accept differential Y input and was termed as the second generation differential
voltage current conveyor (DVCCII). It was shown that the DVCCII was partic-
ularly attractive element for realizing a floating inductance circuit using all
grounded passive components namely, only two grounded resistors along with
a grounded capacitor.
• 1991: Toumazou et al. [ 25 ] proposed the operational floating conveyor (OFC)
characterized by the port relationships V x ¼ V y ,i y ¼ 0, V w ¼ i w .

A bipolar implementation of the OFC was given and it was demonstrated that the
new building block exhibited the gain bandwidth independence of typical
current mode circuits and was suitable for monolithic integration. It was also
shown that the OFC is an attractive element for realizing accurate, closed loop,
current amplifiers and current convertors including closed loop Current
Conveyors.
• 1993: Fabre and Saaid [ 27 ] presented a four-port translinear building block
which was essentially a CCI followed by a voltage buffer and could implement
a gyrator using transistor arrays such as ALA200 from ATT.
• 1995: In [ 28 ], A new type of CC termed as the third generation CC (CCIII) was
introduced by Fabre which is characterized by i y ¼ i x ,v x ¼ v y and i z ¼ i x.
The CCIII was shown to be a useful element for taking out current flowing
through a floating branch of a circuit and it was envisaged that it may be
advantageously employed as the input cell of the probes and current measuring
devices.
• 1996: A new versatile building block called differential difference Current
Conveyor (DDCC) was introduced by Chiu et al. [ 29 ]. It was shown to be useful
for realizing a number of nonlinear functional circuits such as multiplier, squarer
and square rooter in conjunction with MOSFETs and was also shown to be
convenient in realizing universal voltage mode and current mode biquads.
• 1996: In [ 30 ], Wu and Al-Masry introduced a multiple output Current Conveyor
(MOCC) containing both positive and negative outputs.
• 1997: Elwan and Soliman [ 32 ] introduced the so-called differential voltage
Current Conveyor (DVCC) as an extension of CCII. However, it went unnoticed

Z t i x and i z ¼