A review of the two types of circulators using Operational Amplifiers (OA) with detailed comparison is given. Novel active circulator circuits using Current Conveyors (CCII) and Current Feedback Operational Amplifiers (CFOA) and Differential Voltage Current Conveyor (DVCC) are introduced. The proposed CCII circulator circuit uses six CCIIs and three floating resistors. Two different circulator types using the CFOA are given. A circulator circuit which uses three DVCCs and has the advantage of using three grounded resistors is also introduced. Spice simulation results using 0.5 μm CMOS transistors are included to support the theoretical analysis and demonstrate comparisons among the different types of circulators.
In this study, a new ultra-low voltage and ultra-low power voltage differencing buffered amplifier (VDBA) based on dynamic threshold voltage MOS transistors (DTMOS) is proposed. A voltage mode filter configuration is also presented as an application for the proposed VDBA. This filter employed two VDBA blocks and two passive components. The total power consumption of VDBA block is found simply 6.22 nW at a 0.4 V supply voltage. The simulation results by using LTSpice Program with 0.18 μm TSMC CMOS technology model parameters are carried out to show the performance of the proposed active device and its filter applications.
Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights.