Differential Difference Current Conveyor (DDCC) Based Schmitt Trigger Circuit & Its Application

A new voltage mode Schmitt trigger and its application using Differential Difference Current Conveyor (DDCC) is presented in this paper. The proposed circuit has a single DDCC block & two passive components. This circuit does not have any matching conditions. Here two passive components are used and one of them is grounded .The proposed circuit is simulated on SPICE platfor

A novel triangular wave quadrature oscillator without passive components for sinusoidal pulse width modulation DC-AC power conversion

In this study, a low-cost quadrature triangle oscillator using a voltage-controlled closed-loop dual operational amplifier (Op-Amp) architecture is proposed. Unlike other typical designs, this oscillator does not require any passive components. The use of an Op-Amp-based circuit is attractive for a triangle oscillator because it is more cost-effective than a microcontroller-based solution. This is especially true for sinusoidal pulse width modulation (SPWM) DC-AC power conversion applications. The slew-rate restriction of an Op-Amp is a useful characteristic for producing a triangle waveform when seen from the perspective of wave shaping techniques. The MC4558 and the JRC4558D are two examples of dual Op-Amps that are evaluated, contrasted, and described in this article. At supply voltages of +7 V and -7 V, the suggested quadrature triangle oscillator that uses Op-Amps MC4558 and JRC4558D has the same oscillation frequency, which is 63 kHz, as demonstrated by simulation and experimental data. The frequency stability is estimated to be around 0.23%. In addition, the findings from the experiment demonstrate that the proposed oscillator is a practical solution for the SPWM DC-AC power conversion application

Damping Power System Oscillations Using an SSSC-Based Hybrid Series Capacitive Compensation Scheme

Interconnection of electric power systems is becoming increasingly widespread as part of the power exchange between countries as well as regions within countries in many parts of the world. There are numerous examples of interconnection of remotely separated regions within one country. Such are found in the Nordic countries, Argentina, and Brazil. In cases of long distance AC transmission, as in interconnected power systems, care has to be taken for safeguarding of synchronism as well as stable system voltages, particularly in conjunction with system faults. With series compensation, bulk AC power transmission over very long distances (over 1000 km) is a reality today. These long distance power transfers cause, however, the system low-frequency oscillations to become more lightly damped. As a result, many power network operators are taking steps to add supplementary damping devices in their systems to improve the system security by damping these undesirable oscillations. With the advent of voltage sourced converter-based series compensation, AC power system interconnections can be brought to their fullest benefit by optimizing their power transmission capability, safeguarding system stability under various operating conditions and optimizing the load sharing between parallel circuits at all times. This thesis reports the results of digital time-domain simulation studies that are carried out to investigate the effectiveness of a phase imbalanced hybrid single-phase-Static Synchronous Series Compensator (SSSC) compensation scheme in damping power system oscillations in multi-machine power systems. This scheme, which is feasible, technically sound, and has an industrial application potential, is economically attractive when compared with the full three-phase-SSSC. Time-domain simulations are conducted on a benchmark model using the ElectroMagnetic Transients Program (EMTP-RV). The results of the investigations have demonstrated that the hybrid single-phase-SSSC compensation scheme is very effective in damping power system oscillations at different loading profiles

Audio system based on analog electronics : signal processor and valve amplifier

The goal of this project is to design and assembly an audio system based on analog electronics which can have several applications. The purpose is to design and assembly a modular audio system, this means that we will have different subsystems that can be used independently or connected together. Concretely, we will have two subsystems, a signal processor and an amplifier based on one valve, each one with one input and one output. We will be able to introduce an audio signal at the input and obtain an output audio signal on each subsystem.Ingeniería de Sistemas Audiovisuale

New Electronic Interface Circuits for Humidity Measurement Based on the Current Processing Technique

The paper describes a new electronic conditioning circuit based on the current-processing technique for accurate and reliable humidity measurement, without post-processing requirements. Pseudobrookite nanocrystalline (Fe2TiO5) thick film was used as capacitive humidity transducer in the proposed design. The interface integrated circuit was realized in TSMC 0.18 mu m CMOS technology, but commercial devices were used for practical realization. The sensing principle of the sensor was obtained by converting the information on environment humidity into a frequency variable square-wave electric current signal. The proposed solution features high linearity, insensitivity to temperature, as well as low power consumption. The sensor has a linear function with relative humidity in the range of Relative Humidity (RH) 30-90 %, error below 1.5 %, and sensitivity 8.3 x 10(14) Hz/F evaluated over the full range of changes. A fast recovery without the need of any refreshing methods was observed with a change in RH. The total power dissipation of readout circuitry was 1 mW

A simple current-mode Schmitt trigger employing only single MO-CTTA

Abstract- A new current-mode Schmitt trigger based on MO-CTTA (Multiple output current through transconductance amplifier) is presented in this article. The circuit description is very simple, its construction consists of only single MO-CTTA. The hysteresis and amplitude of the output current can be tuned independently/electronically. With mentioned features, it is very suitable to realize in a monolithic chip. The PSPICE simulation and experimental results are depicted, and agree well with the theoretical anticipation. The maximum power consumption is approximately 249mW at ±5V supply voltages. I

Design of Signal Generators Using Active Elements Developed in I3T25 CMOS Technology Single IC Package for Illuminance to Frequency Conversion

This paper presents a compact and simple design of adjustable triangular and square wave functional generators employing fundamental cells fabricated on a single integrated circuit (IC) package. Two solutions have electronically tunable repeating frequency. The linear adjustability of repeating frequency was verified in the range between 17 and 264 kHz. The main benefits of the proposed generator are the follows: A simple adjustment of the repeating frequency by DC bias current, Schmitt trigger (threshold voltages) setting by DC driving voltage, and output levels in hundreds of mV when the complementary metal-oxide semiconductor (CMOS) process with limited supply voltage levels is used. These generators are suitable to provide a simple conversion of illuminance to frequency of oscillation that can be employed for illuminance measurement and sensing in the agriculture applications. Experimental measurements proved that the proposed concept is usable for sensing of illuminance in the range from 1 up to 500 lx. The change of illuminance within this range causes driving of bias current between 21 and 52 mu A that adjusts repeating frequency between 70 and 154 kHz with an error up to 10% between the expected and real cases

Engineering studies related to geodetic and oceanographic remote sensing using short pulsed techniques

Theoretical basis is presented for a feasibility study of measuring global ocean surface current pattern from satellites and aircraft. The analysis is supported by some preliminary laboratory experiments. Since the ultimate goal is to establish an operational routine for monitoring the global current pattern, a nondisturbing remote sensing device using a laser probe was developed. Detailed construction of the measuring system and the results of some preliminary observations are also presented

DAMPING POWER SYSTEM OSCILLATIONS USING A STATCOM AND A PHASE IMBALANCED HYBRID SERIES CAPACITIVE COMPENSATION SCHEME

Interconnection of remotely power systems with large generation capacity and system load is progressively widespread due to the increase of the power exchanges between countries as well as regions within countries in many parts of the world. In the cases of long distance AC transmission, as in interconnected power systems, care has to be taken for maintaining synchronism as well as stable system voltages, particularly in conjunction with system faults and line switching. With series compensation, bulk AC power transmission over very long distances (1000 km and more) is in existence today. These long distance power transfers cause, however, the system low-frequency oscillations, typically within the range of 0.4 to 2 Hz, to become more lightly damped. For this reason, many power network operators and utilities are taking steps to add supplementary controls in their systems to provide extra system damping aiming to improve the system security by damping these undesirable oscillations. This thesis reports the results of time-domain simulation studies that are carried out to investigate the effectiveness of supplemental controls of a phase imbalance hybrid single-phase-Thyristor Controlled Series Capacitor (TCSC) compensation scheme and a static synchronous compensator in damping power system oscillations. In this context, studies are conducted on a typical large power system incorporating several series capacitor compensated transmission lines and large load centers with their reactive power support provided by static synchronous compensators (STATCOM). Several case studies investigating the effects of the location of the hybrid single-phase-TCSC compensation scheme, the degree of compensation provided by the scheme, the stabilizing signals of the supplemental controls, the fault clearing time, as well as the fault location on the damping of power system oscillations are documented. The results of the investigations conducted in this thesis demonstrate that the supplemental controls are very effective in damping power system oscillations resulting from clearing system faults. The time-domain simulation studies are conducted using the ElectroMagnetic Transients program Restructured Version (EMTP-RV)