จำนวน Repository ( 13 )
เครื่องกรองความถี่แบนด์พาสชนิดแอคทีฟที่ปรับตัวได้โดยใช้วงจรแทคโคมิเตอร์
This thesis presented the design and construction of an adaptive active band-pass filter by using a tachometer circuit. The main part was the multi voltage-mode filter circuit based on an operational transconductance amplifier which could automatically adjust the center frequency to adapt to the input signal frequency by the tachometer circuit. The frequency error value in the center frequency was set to be ≤ 3% of the input signal. Furthermore the proposed filter could support the input signal in the frequency range of 10 Hz - 10 kHz. From the simulation and experimental results of the proposed prototype filter it could respond to the frequency according to the theory of the band-pass filter and the error in choosing the center frequency which was 1.45 % and 2.6 % respectively (below the set error value of 3 %). Therefore the proposed filter could be used for real application. The working principles of the proposed prototype filter could also be applied to the noise attenuation circuit of an electrocardiogram machine. Moreover this research could be used as a guideline study for those who want to develop other types of adaptive active filters for higher efficiency.
การวิเคราะห์เซอร์กิตเบรกเกอร์115 kV สำหรับการวางแผนซ่อมบำรุง
HV power distribution system circuit breaker are important devices in substations. Such as Malfunction or deterioration of equipment with in the substation will directing impact on the stability of the power distribution system and affect the reliability of the system. In addition this means that it is necessary to assess the actual condition of the proper condition-based operation and maintenance. Thus this thesis presents condition assessment procedure for equipment by using technical information visual inspection by Weighted Scoring Method. Weighting technique is used to determine important weight testing methods of devices by using Analytic Hierarchy Process (AHP). Testing methods for circuit breaker are such as visual inspection contact timing test. Scoring technique is divided into 1-3 levels by classifying on actual evaluate equipment consisting of consisting of good moderate bad. This thesis proposes a software development in order to organize the database and calculate the analysis of the condition of equipment in 5 HV substations. The evaluation results will be divided into 3 levels good medium and bad condition. According to the evaluation level the maintenance types are separated into 1) regular maintenance 2) increase the frequency of maintenance and monitoring of the test 3) equipment must be improved urgently. Finally abnormal incidents of equipment and cost of HV equipment maintenance can be reduced in effective way.
การออกแบบการทดลองเพื่อปรับปรุงกระบวนการเชื่อมลวดวงจรไฟฟ้าของวงจรรวม
Using copper wire instead of gold wire can reduce a lot of cost in IC production of semiconductor industrial. However the circuit stability (Circuit Reliability) is less than the use of goal wire. Therefore the study to improve the production of integrated circuits in the part of the wire bonding process by increasing the baking process. It is an important process to improve the quality of the integrated circuit between Cu wire and chip. For this experimental study of baking process it was performed by comparing IMC values at 175 ˚C and 200 ˚C. The quality of workpiece was tested and measured by Scanning Electron Microscope (SEM) machine every 30 minutes. The research experiment found that the temperature with effect to the workpiece quality to stabilize the IMC value was 175 ˚C for 9 hours nevertheless the new temperature at 200 ˚C it has been applied with only 3 hours. Finally the IMC testing result is higher than the average of the at 60% standard acceptable level as other research reviews and it also higher than the acceptable level of the industry level at 80%. Hence this result can reduce time cost of IC and workpieces production and it also including the higher quality of the products.
ผลกระทบจากเอ็นบีทีไอต่อสมรรถนะของวงจรรวมดิจิทัลที่สร้างด้วยเทคโนโลยีฟินเฟต
In FinFET-based VLSI designs heat issues from increase of driving current with temperature and self-heating effect profoundly influence the circuit performance and reliability. This work evaluates the performance of FinFET-based combinational circuits considering BTI stress and thermal effect of supply voltage and frequency variations. The proposed simulation framework is applied to selected benchmark circuits implemented with the 14-nm tri-gate bulk FinFET technology. The experimental results reveal that as temperature increases BTI aging delay increasingly worsens yet it is overridden by performance gain from the increase in driving current. We also prove that BTI degradation is dependent on power supply and frequency through their thermal impacts. Further we introduce a DVFS based power reduction approach that scales down the supply voltage of hot circuits to maintain the performance. The results show that power reduction yielded from the proposed technique is larger for all circuits working at higher ambient temperature (as large as 66% in some experimental circuits working at 20 oC above the baseline ambient temperature) with a slight decrease in BTI degradation.
การประเมินผลกระทบของการลัดวงจรในระบบจำหน่ายไฟฟ้าที่มีต่ออุปกรณ์วิกฤต
This research presents the studying of short circuit in distribution system that affect to critical equipment voltage sag and overvoltage while short circuit event. Lead into the quality of electric user. Effect on economics damaged Distribution system voltage level 22kV of The Provincial Electricity Authority. It is the analysis model by computer program. The event of short circuit set in a many distribution systems. The analysis result Magnitude of voltage while short circuit bring to assessment voltage sag and overvoltage from average voltage of the repeat event. Then set boundary of voltage at load point in a many. The experiment shows the problem of the quality of electric be affect to critical equipment less than load point close connection with substation.