The classification of universal amplifiers presented in this paper places all operational amplifiers and current conveyors known from the literature into a common framework, together with abstract concepts such as the universal active element and the nullor. Our approach is new in that we base it on four-terminal theory, which results in a classification that is more extensive but not more complex than classifications derived using two-port theory. It turns out that our classification contains a new type of operational amplifier, which we call current-feedback operational transconductance amplifier (CFB OTA), and also a new class of voltage-inverting current conveyors. We then demonstrate that our classification is very closely related to integrated-amplifier design by showing how all operational amplifiers and current conveyors can be implemented in CMOS using only a few CMOS circuits. Since the basic ideas behind CMOS and bipolar circuits are very similar, this paper is not process specific and can be seen as an attempt to bridge the gap between amplifier theory and amplifier design that has become ever wider in the past few years.

In this work, new oscillator topologies based on a recently introduced active element, namely inverting second-generation current conveyor, are presented. This recently introduced unity gain based active element is suitable for integrated circuit realization and can easily be implemented with CMOS technology. Considering this fact, basic oscillator topologies employing a single, two and three conveyors are proposed. Several oscillator circuits based on these topologies are obtained. Expressions for oscillation conditions and frequencies are derived both for ideal and non-ideal cases. Some of them are single frequency and the others are variable frequency oscillators. The oscillators employing two and three active elements use only grounded passive elements. The presented oscillators are tested with SPICE simulations to verify the theoretical results. 1.