Non-inverting Amplifier Research Articles

High voltage formation using the amplifiers cascading method

The dividing of high voltage broadband non-inverting cascade amplifiers into separate cascades, each of which has independent power sources, is suggested. These cascades are connected to one another in series, switching on the operational amplifiers and the feedback links. The gain of each cascade is determined by the non-inverting scheme of feedback that assures accurate signal processing. To provide stable and effective functioning, the operational amplifiers are supplied with power from transistor repeaters. That assures the required feeding voltage levels. Due to the thorough selection of the gain factor and feeding source voltage, the amplifier system achieves the expended output voltage range.

Design of Photoelectric Positioning System and Realization of Its Positioning Mathematical Equation

The research of photoelectric positioning system based on wireless data transmission is a multidisciplinary research direction. In the design of photoelectric positioning system, the LED used for light sensing is selected as the light source, and the AC/DC isolated LED driving circuit based on AP3706 is designed. When designing photoelectric conversion circuit, considering the influence of noise interference on detection accuracy, a capacitor is added and connected in parallel with the feedback capacitor. In order to improve the detection accuracy, reduce the relative error of the four-channel signal processing process and maintain the consistency of the four channels, a noninverting amplifier circuit composed of four operational amplifiers LM324 amplifier chips is adopted in this study. NewMsg-RF2401 module is used for wireless data transmission. The system control module adopts ADμC841 single chip microcomputer as the control core. According to the characteristics of this single chip microcomputer, the corresponding ADC module input drive circuit and control-data transmission interface circuit are designed. While designing the hardware of the system, it is necessary to calculate the positioning position. In this study, a positioning mathematical equation is proposed, which can obtain the position of the moving target in the geographical area under the wireless transmission network. In the experiment, firstly, the implementation process of the positioning mathematical equation is described, and then the performance of the proposed positioning mathematical equation is compared with that of the random positioning equation and the binary positioning equation. The results show that more messages can be transmitted by using the positioning mathematical equation proposed in this study. Based on this, it is used in the positioning system designed in this study, which is unfolded under the condition of constant background light, adjusts the position of the movable light source and determines the position coordinates. According to the horizontal and vertical displacement of the light source detected by the system, the positioning error is less than 0.1%, which is in line with the design expectation.

An 800MΩ-Input-Impedance 95.3dB-DR Δ-ΔΣ AFE for Dry-Electrode Wearable EEG Recording.

Non-invasive, closed-loop brain modulation offers an accessible and cost-effective means of evaluating and modulating one's mental and physical well-being, such as Parkinson's disease, epilepsy, and sleep disorders. However, wearable EEG systems pose significant challenges for the analog front-end (AFE) circuits in view of µV-level EEG signals of interest, multiple sources of interference, and ill-defined skin contact. This paper presents a direct-digitization AFE tailored for dry-electrode scalp EEG recording, characterized by wide input dynamic range (DR) and high input impedance. The AFE utilizes a second-order 5-bit delta-delta sigma (Δ-ΔΣ) ADC to shape DC electrode offset (DEO) and low-frequency disturbances while retaining high accuracy. A non-inverting pseudo-differential instrumentation amplifier (IA) embedded in the ADC ensures high input impedance (Zin) and common-mode rejection ratio (CMRR). Fabricated in a standard 0.18-μm CMOS process, the AFE delivers 700-mVpp input signal range, 95.3-dB DR, 87-dB SNDR, and 800-MΩ input impedance at 50 Hz while consuming 88.4µW from a 1.2 V supply. The benefits of high DR and high input impedance have been validated by dry-electrode EEG measurement.

Improving Selected Electrical Engineering Students’ Abilities of Using Technological Tools

This article deals with the effects of using technological lab tools, specifically inverting and non-inverting operational amplifiers, on improving the abilities of 3rd-year Electrical Engineering students at the University of Gondar, Ethiopia. It has cultivated a culture of continuous improvement and collaboration of eighteen students who were grouped into three teams. The performance of students’ ability was evaluated using tests, attitude, and creativity measurements. The tests were administered just to measure the student's knowledge and skills before and after the intervention. Besides, a questionnaire was employed to measure the overall use of electronic lab tools during the actual training sessions. Gaps or issues on two applied electronics lab tools were seen concerning the current curricula and instructional strategies, student performance and understanding, motivation, and involvement of students, and comments from both teachers and students. On the other hand, students were supposed to relate and blend their theoretical knowledge with practical abilities when they access to exchange practical skills. Towards this end, they were guided to do the same design circuit across groups. Empirical data were gathered from peer assessment and observation, and pre-and post-tests were described descriptively considering time. The findings indicated a significant improvement in students' comprehension and performance when utilizing technological tools during electronics lab training periods. The implementation of an inverting operational amplifier improves the test score of the student by 41.11%. There was an increase in both technical proficiency and problem-solving skills among the participants.

Perancangan dan Pembuatan Data Acquisition Device Sebagai Sistem Akuisisi Data untuk Kendali Mobil Formula Student

Data Acquisition Device (DAQ) is an electronic component used in formula student vehicles. To optimize the performance of the formula student vehicle and its driver, it is necessary to analyze and monitor the data acquisition system. Parameters acquired on the car include the position of the brake pedal/throttole and wheel speed.DAQ system has 5 input channels namely 3 analog input pins and 2 digital input pins, and 3 output channels, which is the controller pin, fault pin, and brake light pin. The DAQ system in this research is designed and made using Teensy 3.6, a signal conditioning circuit consisting of an RC low pass filter, voltage follower, non-inverting amplifier, and logic level shifter. DAQ system uses CANBUS to read and process sensor data. DAQ system can acquire data from the KTC Linear Motion Position sensor PZ-12-A-50P with an accuracy value of 99,91%; Hall-effect Rotary Position sensor RTY120LVNAX with an accuracy value of 99,94% for both the first and second sensors; and Proximity sensor LJ12A3-4-Z/BX with an accuracy value of 99,58% for the first sensor and 99,46% for the second sensor. DAQ is able to run controller signal processing, detect faults, and activate brake light signal according to FSAE rules.

Design Of High-Speed Low Voltage Operational Amplifier

Background: The Operational amplifier (op-amp) is the building block of linear integrated electronics, therefore proposing newer design models with improved parameters is an essential landmark in the electronics industry in the hunt for a faster and more efficient design. Objective: To attain high speed and low power supply, the authors designed an op-amp using three different techniques. Initially compensating network was designed and simulated but the resultant output voltage saturates in inverting and non-inverting modes. Methods: Voltage feedback op-amp (VFOA) and current feedback op-amp (CFOA) were proposed to achieve the target. The authors have successfully designed the circuit, but the power dissipated is less and Common Mode Rejection Ratio (CMRR) is high in CFOA in comparison to VFOA. Results: The results are simulated for three different configurations and inverting configuration results in remarkable results in comparison to a non-inverting and differential amplifier. Inverting configuration using VFOA results in 91.22dB, and 0.0131W CMRR and power dissipation, respectively, while that of CFOA results in 97.34dB, and 0.0129W CMRR, and power dissipation, respectively. Conclusion: 1.6% improvement in CMRR and a 26.8% improvement in power dissipated for the proposed CMOS CFOA in comparison to the proposed VFOA. All the validations are done by plotting the bode plot and Nyquist plot.

A TRIZ-Adopted Development of a Compact Experimental Board for the Teaching and Learning of Operational Amplifier with Multiple Circuit Configurations

Operational amplifiers (op-amps) are generally used for actualizing simple and complex electronic circuits in the subject of analogue electronics. In an effort to improve the teaching of op-amps in electronics engineering curricula, op-amp circuits in various configurations are often used for experiments in laboratory sessions so that students can acquire certain psychomotor and cognitive skills by constructing circuit connections and analyzing input–output waveforms. As a result, multiple configurations of operational amplifier circuits are often needed, requiring multiple sets of experimental boards or circuits for each experiment. This is usually not cost effective, requires more consumable electronic components, requires more maintenance and storage space in facilities, and is less user friendly for the students. Therefore, the aim of this research is to design a single, compact, and easy-to-replicate experimental board that can be converted into multiple configurations of the LM741 operational amplifier, comprising an inverting amplifier, a noninverting amplifier, a voltage follower, a summing amplifier, a differential amplifier, a differentiator, and an integrator, with minimal electronic components at a cost lower than EUR 10. The experimental board was tested with a constant input voltage of 1.0 V AC and a switching frequency of 1.0 kHz. It is capable of producing an output voltage corresponding to the individual operational amplifier configurations and can thus be used as a facilitating module for teaching and learning activities in the field of analogue electronics.

Enhancing Digital Filtering to Electrocardiogram Analysis: Butterworth Filter Application

The electrocardiogram (ECG) of the human body is an important basis in heart function as well as the diagnosis of cardiovascular diseases, which has a very vital role in clinical diagnosis. Obtaining high-quality ECG signals with a portable remote ECG acquisition system is a big challenge given limited resources. According to the World Health Organization (WHO), disorders of the cardiovascular system still rank high, causing about 31% of deaths globally. This is because the symptoms of cardiovascular disease cannot be seen directly, but rather by conducting an electrocardiograph (ECG) examination. The purpose of this research is to record the electrical signals of the heart by comparing the 2nd order AD8232 module analogue filter with the 8th order Butterworth digital filter which is a better signal for easier reading. This research uses a multiplexer circuit for switching leads, AD8232 ECG module, 50Hz notch filter circuit, non-inverting amplifier, adder, Arduino Mega 2560, USB module, and an application to display digital signals, namely Delphi 7. Signal acquisition is done by monitoring for one minute. Data collection was carried out with 5 respondents 5 times on each lead. The results of the data collection can be concluded that 80% of digital filters display smoother signals for ECG signals than analogue filters

Signal processing and noise analysis on realistic radiation detector model

In this paper, equations for signal processing and noise analysis were derived for a realistic radiation detector model, and simulations were performed under various conditions. Realistic radiation detector model was composed of silicon PIN diode detector, Charge Sensitive Amplifier (CSA), and CR-RC2 shaper. For the realistic CSA model, a finite bandwidth model with a single pole response amplifier was presented and related equations were derived. Through realistic CSA model, it was possible to calculate the signal distortion phenomena such as charge transfer loss and ballistic deficit of the actual circuit and the noise value of the CSA output stage. For the realistic shaper model, signal and noise transfer functions were derived for the CR-RC2 circuit with non-inverting amplifier. In particular, the equation for the internal noise of the shaper, which has been ignored in the current noise analysis, was derived. Through this, it was possible to analyze the effects of amplifier characteristics, resistance value, and signal gain for each stage on the overall noise in the radiation detector of the CSA–shaper structure. For comparison with the simulation, a circuit equivalent to the realistic radiation detector model was made and measurements under the same conditions as the simulation were made. As a result of the verification experiment, the measured values matched well with simulations under various conditions, and through this, the validity of this model was verified. Signal processing and noise analysis were mainly performed for PCB circuits using commercial components, but also included content for CMOS front-end detectors. This model consists only of analytic formulas for the time domain function and the transfer function, nonetheless it has been shown to give accurate results.

Bandwidth and Common Mode Optimization for Current and Voltage Sources in Bioimpedance Spectroscopy.

Bioimpedance measurements use current or voltage sources to inject an excitation signal into the body. These sources require a high bandwidth, typically from 1 kHz to 1 MHz. Besides a low common mode, current limitation is necessary for patient safety. In this paper, we compare a symmetric enhanced Howland current source (EHCS) and a symmetric voltage source (VS) based on a non-inverting amplifier between 1 kHz and 1 MHz. A common mode reduction circuit has been implemented in both sources. The bandwidth of each source was optimized in simulations and achieved a stable output impedance over the whole frequency range. In laboratory measurements, the output impedance of the EHCS had its -3 dB point at 400 kHz. In contrast, the VS reached the +3 dB point at 600 kHz. On average over the observed frequency range, the active common mode compensation achieved a common mode rejection of -57.7 dB and -71.8 dB for the EHCS and VS, respectively. Our modifications to classical EHCS and VS circuits achieved a low common mode signal between 1 kHz and 1 MHz without the addition of complex circuitry, like general impedance converters. As a conclusion we found VSs to be superior to EHCSs for bioimpedance spectroscopy due to the higher bandwidth performance. However, this only applies if the injected current of the VS can be measured.

A Two Channels Wireless Electrocardiograph System Using Bluetooth Communication

Health problems with cardiovascular system disorders are still ranked high, according to data from the WHO reported that there are about 31% of causes of death globally are cardiovascular diseases. The purpose of this study was to develop a 12 lead electrocardiograph with 2 displays and the HC-05 as a real-time transmitter of heart signal data. The electrocardiogram signal is obtained from the wiretapping by attaching the electrode cable to the Lead I, Lead II, Lead III, aVR, aVL, and aVF leads, then processed on IC AD620, HPF and LPF filters and non-inverting amplifiers and then processed using Arduino UNO for further display. in the form of a signal on the Delphi 7 application. The research method is to measure the heart signal on the ECG Simulator, by testing several BPMs, namely 30, 60, 120 and 240 on each lead. After testing the signal equation at the 0.5mV setting by calculating the error rate, the highest error value is obtained in lead I, lead aVL and aVF of 7.14% and the smallest error is 3.57% error in lead III. Then at the 1mV setting by calculating the error rate, the highest error value in lead aVL is 7.14% and the smallest error is 2.36%. at the 2mV setting by calculating the error rate, the highest error value is obtained in leads aVL and aVF of 5.71% and the smallest error is obtained by an error of 2.1% in lead II. the results of this study are implemented so that in the future an ECG examination can be carried out and then monitored remotely like a doctor's room because the data communication uses bluetooth.

Probability distribution function of crossover frequency of operational amplifiers

For the first time the cumulative distribution function and histogram of the crossover frequency of a contemporary operational amplifier ADA4898-2 is experimentally studied. Using a USB lock–in amplifier, which allows automatic frequency sweep of the current response of a non-inverting amplifier with significant static amplification, we measure the crossover frequency of 200 samples of ADA4898-2 operational amplifiers. This new method gives a significant advantage in accuracy and speed of study of every operational amplifier. The theory we use is based on the universal relation between time dependent output and input voltages. This common relation for all operational amplifiers is applicable for frequencies much smaller than the crossover frequency and the frequencies of non-dominant poles. In other words, this approximation is adequate, when an operational amplifier is included in a circuit with significant amplification.

Improving the Drift Effect and Hysteresis Effect of Urea Biosensor Based on Graphene Oxide/Nickel Oxide Sensing Film Modified Either by Au Nanoparticles or γ-Fe₂O₃ Nanoparticles Using Back-End Calibration Circuit

From our other works, we have developed urea biosensor based on graphene oxide/nickel oxide sensing film modified either by Au nanoparticles or <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\gamma }$ </tex-math></inline-formula> -Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> nanoparticles. In this study, we have further developed back-end calibration circuit to reduce the drift effect and hysteresis effect of the two types of the urea biosensors. The back-end calibration circuit is composed of non-inverting amplifiers, error amplifiers, P-MOSFET transmission transistor, feedback networks, output voltage capacitors and resistor dividers. After applying the back-end calibration circuit, the drift rate of urea biosensor modified by Au NPs is reduced from 3.06 mV/hr to 0.28 mV/hr, which is 90.85% reduction. The drift rate of urea biosensor modified by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\gamma }$ </tex-math></inline-formula> -Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> NPs is reduced from 3.92 mV/hr to 0.57 mV/hr, which is 85.46% reduction. Through the back-end calibration circuit to reduce the hysteresis effect, the hysteresis voltage for the forward cycle and reverse cycle of the urea biosensor modified by Au NPs are reduced by 26% and 30%, respectively. The hysteresis voltage for the forward cycle and reverse cycle of the urea biosensor modified by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\gamma }$ </tex-math></inline-formula> -Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> NPs are reduced by 23% and 28%, respectively.

A High-Voltage and Low-Noise Power Amplifier for Driving Piezoelectric Stack Actuators.

In this paper, based on the principles of general operational amplifiers, a high-voltage operational amplifier is developed. Considering the influences of piezoelectric stack actuators on the circuit, a novel structure using the high-voltage operational amplifier as a noninverting amplifier is proposed. Because of the simple circuit principles and the voltage feedback control structure, the proposed power amplifier has the advantages of low noise and small size, and it can be realized by discrete electric elements easily. In the application of precision positioning, a power amplifier using the proposed circuit principles for driving piezoelectric stack actuators is designed, simulated, and tested. The simulated results show that the proposed power amplifier could conform to the theory of the circuit. The experimental results show that the designed power amplifier conforms to the simulation, the bandwidth of the power amplifier is about 57 kHz, and the ripple of the power amplifier is less than 2 mV. Furthermore, the output of the proposed power amplifier maintains the same type of wave within in a large range of frequency, while the input is the sinusoidal or square wave, and the resolution of the mechanism which the power amplifier is applied in is about 4.5 nm. By selecting the critical electronic elements and using feedback control, the proposed circuit structure is able to realize a low-cost and high-performance power amplifier to drive piezoelectric stack actuators flexibly, which is the novel work of the paper.

Prosthetic hand with 2-dimensional motion based EOG signal control

A prosthetic hand is an artificial device that resembles a human hand which can help the human with a physical disability. Previously, the development of a prosthetic hand is designed in various method, from passive to bionic. Electrooculography (EOG) is a technique for measuring potential differences between the front (positive pole formed by the cornea) and the back (negative pole formed by the retina) of the eyeball which can be used to detect eye movements. The purpose of this study is to design a prosthetic hand with two degrees (2D) of freedom using EOG based control. This system consists of electrodes, EOG amplifier, Bluetooth transmitter-receiver, servo motors, and hand prosthetics. In this study, the system will recognize the eye movements, namely front, right, left, up, and down. The system will recognize the motion based on a threshold value. In the hardware implementation, the system was composed of five electrode sensors which installed around the eye, instrumentation amplifier, high pass filter, low pass filter, noninverting amplifier, summing amplifier, a notch filter circuit, and Arduino UNO microcontroller. In EOG data acquisition, this study involved ten healthy subjects. After the evaluation with five trial for each motion, the error for each eye movement is 0%, 0%, 36%, 4% and 16% for right, left, top, bottom, and front, respectively. This study provided an alternative method to control a prosthetics hand with good performance.

Design of analog circuit of photomultiplier tube array for wide field of view Cherenkov telescope array of LHAASO

The wide field of view Cherenkov telescope array (WFCTA) of the Large High Altitude Air Shower Observatory (LHAASO) is intended to detect atmospheric Cherenkov light or fluorescence. The photomultiplier tube (PMT) array is designed to enable atmospheric monitoring in real time and telescope calibration. This paper introduces the design of the analog circuit for the PMT array. The analog board has 16 channels, where each channel contains a shaping circuit, a high gain circuit and a low gain circuit. The shaping circuit uses a charge integrating circuit, and the amplifier module is composed of a noninverting amplifier circuit and a full differential amplifier circuit. Test results indicate that the dynamic range of the designed circuit is more than 3.2 orders of magnitude, the small signal resolution is less than 20%, the corresponding resolution of large signals is less than 4%, and the relative deviation from linearity is less than 5%. These performance indicators exceed the requirements of the project.

CMOS voltage and current feedback opamps: a comparison between two similar topologies

ABSTRACT The voltage feedback operational amplifier (VFOA) and the current feedback operational amplifier (CFOA) are the main voltage type output opamps currently used in electronics. The VFOA is a combination of an operational transconductance amplifier (OTA) used as an input stage and an output voltage buffer (VB). In this paper, the CFOA is described as a combination of an operational transconductance conveyor (OTC) used as an input stage and with an output voltage buffer. Two similar CMOS architectures are then defined, analysed and simulated in order to provide some elements of comparison. Results, from a typical CMOS 0.35μm transistor parameters, show the role of compensation capacitances in boosting the frequency performances of the non-inverting amplifier.

Low-Concentration Ammonia Gas Sensors Manufactured Using the CMOS-MEMS Technique.

This study describes the fabrication of an ammonia gas sensor (AGS) using a complementary metal oxide semiconductor (CMOS)–microelectromechanical system (MEMS) technique. The structure of the AGS features interdigitated electrodes (IDEs) and a sensing material on a silicon substrate. The IDEs are the stacked aluminum layers that are made using the CMOS process. The sensing material; polypyrrole/reduced graphene oxide (PPy/RGO), is synthesized using the oxidation–reduction method; and the material is characterized using an electron spectroscope for chemical analysis (ESCA), a scanning electron microscope (SEM), and high-resolution X-ray diffraction (XRD). After the CMOS process; the AGS needs post-processing to etch an oxide layer and to deposit the sensing material. The resistance of the AGS changes when it is exposed to ammonia. A non-inverting amplifier circuit converts the resistance of the AGS into a voltage signal. The AGS operates at room temperature. Experiments show that the AGS response is 4.5% at a concentration of 1 ppm NH3; and it exhibits good repeatability. The lowest concentration that the AGS can detect is 0.1 ppm NH3

Comments on "A novel high input impedance front-end for capacitive biopotential measurement".

A front-end for biopotential sensing in wearable medical devices has been recently proposed which is claimed to provide 100GΩ input impedance by manually matching two resistor pairs in a positive- and a negative-feedback loop around an operational amplifier (op amp); the cost being that the equivalent input noise voltage doubles with respect to a simple non-inverting amplifier. The ECG acquired with capacitive (sic) electrodes through a cotton shirt is presented as a proof of the performance of the proposed circuit. It turns out, however, that the analysis ignores op amp's input capacitance hence the effort to achieve a very high input resistance seems futile. Further, cotton is highly hygroscopic hence not an appropriate dielectric, so that there is no proof that the electrodes tested were actually capacitive. This comment addresses these two problems and some additional conceptual and methodological inaccuracies found in the paper.

A New Calibration Circuit Design to Reduce Drift Effect of RuO2 Urea Biosensors.

The goal of this study was to reduce the drift effect of RuO2 urea biosensors. A new calibration circuit (NCC) based on the voltage regulation technique with the advantage of having a simple structure was presented. To keep its simplicity, the proposed NCC was composed of a non-inverting amplifier and a voltage calibrating circuit. A ruthenium oxide (RuO2) urea biosensor was fabricated to test the calibrating characteristics of the drift rate of the proposed NCC. The experiment performed in this study was divided into two main stages. For the first stage, a sound RuO2 urea biosensor testing environment was set-up. The RuO2 urea sensing film was immersed in the urea solution for 12 h and the response voltage was measured using the voltage-time (V–T) measurement system and the proposed NCC. The results of the first stage showed that the RuO2 urea biosensor has an average sensitivity of 1.860 mV/(mg/dL) and has a linearity of 0.999 which means that the RuO2 urea biosensor had been well fabricated. The second stage of the experiment verified the proposed NCC’s functions, and the results indicated that the proposed NCC reduced the drift rate of RuO2 urea biosensor to 0.02 mV/hr (98.77% reduction).