This thesis describes the design and development of a sampling-type function generator and a four-quadrant analog multiplier. The project is divided into two parts, the general arrangement and circuitry of the function generator and multiplier, and the timing circuits which actuate them. This thesis is concerned with the general circuitry. The functions to be generated are photographed on 35 mm. film and mounted in standard frames which are then fastened to the rim of a rotating disk. An optical system is used to scan the functions in a time-sequential manner. A timing system selects the required abscissa and actuates a combination of electronic gates and clamping circuits which stores the voltage, Eք, representing the ordinate, and the voltage, Eм, representing the maximum of the function. These two stored voltages, Eք and Eм, are applied to separate sweep circuits which produce sweep outputs of EքN(t) and EмN(t) respectively. A system of comparator circuits and gates samples the EքN(t) at the instant a reference voltage, E, equals the sweep EмN(t). Since the sweeps, N(t) are identical, the value of EքN(t) at the instant of sampling is (formula not included). This sequence of operations occurs for each function as it is scanned. Each successive multiplication is stored in its own storage unit. All the circuits are designed to be self-calibrating to minimize error due to drift. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Poor academic performance in science is a problem in the world. Numbers of factors contribute to this academic performance. Secondary school learners, particularly those in grade 10 are experiencing problems in understanding simple electric circuits in Physical Sciences. Lack of exposure to practical work might be one of the factors that contribute to lack of understanding of simple electric circuit and inability to link what they learn in class with the outside world. For that reason, it is the purpose of this study to determine what grade 10 learners’ alternative conceptions in electricity are and to explore the impact of conceptual change model on grade 10 learners using simple electric circuits. The study further highlights a number of issues that lead to poor academic achievements in physical sciences. This study further provides the learning strategy in physical science for learners to improve their learning process of simple electric circuits. Four secondary schools from Mankweng cluster, Capricorn District of Limpopo Province were randomly selected to participate in this study. From these schools a sample of 136 learners of different sex were also randomly selected. Two survey instruments, an open-ended questionnaire and the Simple Electric Circuit Conceptual Test were used to collect data. The data was collected over a period of 3 weeks. Learners (in the experimental group) were taught the same electric circuit topics using Conceptual Change Model (CCM) while Regular Teaching Approach (RTP) was used in the control group. Data collected was analysed using descriptive analysis, ANOVA and ANCOVA. The explanations the respondents gave were analysed using nomothetic and ideographic analyses. Misconceptions were identified as one of the learning barriers. The results from the questionnaire also revealed that learners were willing to learn electric circuits’ concepts but they lacked effective learning strategies and techniques to enhance their academic performances. It was also established that learners could not relate what they had learnt on electric circuit with their daily experiences and that practical work was rarely conducted at most schools. The statistical results showed that when teaching simple electric circuits using Conceptual Change Model, there is equal improvement in academic results across all sexes. There was no significant difference between academic achievements of males and females taught using the Conceptual Change Model. / MEd (Natural Sciences Education), North-West University, Potchefstroom Campus, 2014

Poor academic performance in science is a problem in the world. Numbers of factors contribute to this academic performance. Secondary school learners, particularly those in grade 10 are experiencing problems in understanding simple electric circuits in Physical Sciences. Lack of exposure to practical work might be one of the factors that contribute to lack of understanding of simple electric circuit and inability to link what they learn in class with the outside world. For that reason, it is the purpose of this study to determine what grade 10 learners’ alternative conceptions in electricity are and to explore the impact of conceptual change model on grade 10 learners using simple electric circuits. The study further highlights a number of issues that lead to poor academic achievements in physical sciences. This study further provides the learning strategy in physical science for learners to improve their learning process of simple electric circuits. Four secondary schools from Mankweng cluster, Capricorn District of Limpopo Province were randomly selected to participate in this study. From these schools a sample of 136 learners of different sex were also randomly selected. Two survey instruments, an open-ended questionnaire and the Simple Electric Circuit Conceptual Test were used to collect data. The data was collected over a period of 3 weeks. Learners (in the experimental group) were taught the same electric circuit topics using Conceptual Change Model (CCM) while Regular Teaching Approach (RTP) was used in the control group. Data collected was analysed using descriptive analysis, ANOVA and ANCOVA. The explanations the respondents gave were analysed using nomothetic and ideographic analyses. Misconceptions were identified as one of the learning barriers. The results from the questionnaire also revealed that learners were willing to learn electric circuits’ concepts but they lacked effective learning strategies and techniques to enhance their academic performances. It was also established that learners could not relate what they had learnt on electric circuit with their daily experiences and that practical work was rarely conducted at most schools. The statistical results showed that when teaching simple electric circuits using Conceptual Change Model, there is equal improvement in academic results across all sexes. There was no significant difference between academic achievements of males and females taught using the Conceptual Change Model. / MEd (Natural Sciences Education), North-West University, Potchefstroom Campus, 2014

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<p> With the increased use of the internet, artificial intelligence, IoT, and wearable devices, it has become significantly critical to ensure security and confidentiality of information, particularly within these resource-constrained edge devices. The increased attentions to security and confidentially of information led to the development of computationally-secure cryptographic algorithms. At the same time, low-power sensing devices have emerged as highly promising tools for a wide range of technological applications such as diagnostics, physiological monitoring, and healthcare systems. The desire for seamless and continuous monitoring in sensing applications necessitates these devices to be compact in size and exhibit low power consumption, making them suitable for wearable or portable use with batterypowered operation.</p> <p> Keeping this objective in focus, I will structure this dissertation into the subsequent chapters. The first part (Chapter 2) will cover a theoretical analysis of the proposed Co-planar capacitivE Asymmetry SEnsing (CEASE) technique utilizing four on-die top-layer metal plates. Also, it will present the comparison with other sensing methods which are capacitive parallel and inductive sensing technique in terms of detection range through electromagnetic simulation. The second part (Chapters 3) of this this dissertation will involve explore of the concept of capacitive sensing in an IC layout and co-optimizing both the ground plane capacitance and the sensing capacitance to maximize sensitivity. It will present design of the post-processing circuits and systems with ultra-low power for sensing attacks and to prove the efficacy through the post-layout simulation results. Additionally, integration with digital SCA protection and AES-256 crypto core and checking the efficacy of the proposed method using the integrated detection and countermeasure system in post-layout simulations. Next in Chapter 4, we will show the lowest-power and the energy/conversion step time-based RDC for low frequency applications. It will presents the ways to enhance the energy-resolution trade-offs in time-based RDC, improving the rms jitter/phase noise with help of speed-up latches, to achieve higher bit-resolution. Furthermore, the power/performance trade-off in experiment through 3 different design variations optimized towards lowest energy baseline, higher resolution, and process portability tapeout and IC measurements is presented. Finally, in Chapter 5, we will show a novel proposed switchable dual-mode device that combines a high-frequency antenna and a Human Body Communication (HBC) coupler in a single device. The integration of these two modes addresses the limitations of HBC, such as restricted data transmission, and overcomes the drawbacks of signal absorption in the 24GHz frequency band by the human body. </p>

A Web-based circuit design package has been improved and evaluated to provide students with an enhanced and innovative teaching tools package for the electrical circuit design course. The project objectives can be summarized as follows: 1) developing enhanced problem solving skills using a Web-based environment, 2) developing the design skills and sharpening the critical thinking process, 3) developing a generic and comprehensive teaching/learning circuit package as an extention to the Electrical Engineering virtual lab environment, which gives students the capability to practice and experience all the circuit design skills with minimum cost and effort. The project provides the students with an enhanced and powerful graphical computer aided design (CAD) tool by which students can carry out an online simulation of AC and DC designs with the capability to plot simulation results graphically. The proposed prototype is implemented by JAVA, which is used to to implement Web-based applications with different platform support. The project provides students with an enhanced graphical user interface (GUI) by which they can build any electrical circuit using either text or schematic entry format, generate the Netlist, which describes all circuit information (circuit topology, circuit attributes and so on), and simulate the design by parsing the Netlist to CIRML format, which is sent over the network to the remote server. The server will process the CIRML data and run the simulation using PSPICE and eventually send back the simulation results to the client for display.

<p dir="ltr">This work introduces an ultra-low-voltage charge pump for energy harvesters in biosensors. The unique aspect of the proposed charge pump is its two-level design, where the first stage elevates the voltage to a specific level, and the output voltage of this stage becomes the input voltage of the second stage. Using two levels reduces the number of stages in a charge pump and improves efficiency to get a higher voltage gain. In our measurements, this charge pump design could convert a low 85mV input voltage to a substantial 608.2mV output voltage, approximately 7.15 times the input voltage, while maintaining a load resistance of 7MΩ and a 29.5% conversion efficiency.</p>