Practically Realizable Circuits for OTRA and their Implementation in Oscillators

In this paper, practical circuits for operational transresistance amplifier (OTRA) realizable in lab using commercial ICs have been designed and proposed. 3 structures based on operational amplifier (OPAMP-LM741), operational transconductance amplifier (OTA-CA3080) and current conveyors II (AD844) have been proposed. In these proposed designs, conditions to mimic the current-voltage behavior of OTRA have been formulated using active and passive components. Moreover, these components are also used to achieve flexibility in transresistance gain of implemented OTRA. The behavior of the proposed OTRA structures have been validated using LTSPICE. Furthermore, to represent practical usability of these designs oscillator circuit have been designed and implemented on software and experimentally also on bread board. All the results prove the OTRA operation of the designed circuits and their usability in the practical environment.

Full-Phase Operation Transresistance-Mode Precision Full-Wave Rectifier Designs Using Single Operational Transresistance Amplifier

This study proposed the designs of two full-phase operation transresistance-mode (TRM) precision full-wave rectifiers. The first circuit consisted of a single operational transresistance amplifier (OTRA), four diodes, and a resistor. The second scheme was an OTRA combined with a full metal-oxide semiconductor field-effect transistor-based design, which is preferable for integrated circuit implementation because no passive components are used in the circuit topology. Based on our literature review, this is the first study that discussed a full-phase operation transresistance-mode precision full-wave rectifier consisting of a single OTRA and few passive components. In this paper, several previously reported precision full-wave rectifiers consisting of various active devices are first reviewed followed by the proposed OTRA-based transresistance-mode precision full-wave rectifiers and an analysis of nonideal effects. Furthermore, computer simulations and experimental results are presented to verify the validity of the proposed circuits, which were consistent with the theoretical predictions.