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Iontophoresis is a method to enhance and regulate the transdermal drug delivery by application of an electric field to the skin. Application of small electric current (µ A) enhances transport of both charged and neutral molecules across the skin. Reverse of this process enables extraction of analytes across the skin for noninvasive sensing and diagnosis. Hence it is planned to conduct detailed studies on Reverse Iontophoresis. An invitro model is developed to study the extraction of glucose across the skin. Effects of magnitude of electric current, time of application, pH etc. on the extraction of glucose are studied. It is observed that extraction of glucose at the cathode is higher than at the anode. Advantage of invitro model is the possibility of varying parameters to an extent which is impossible invivo. Instrumentation suitable for continuous monitoring of reverse iontophoresis invivo in human subjects is developed. It supplies the required current and acquires the potential profile of the skin during reverse iontophoresis. Potential profiles showed that skin resistance decreases with the application of current. Experimental results revealed that the application of pulsed DC tends to make the reverse iontophoresis more effective by enhancing the flow of analytes which is proved by the fact that skin resistance decreases and stabilizes faster in comparison to the one with direct current reverse iontophoresis. Present work emphasizes the importance of selecting an appropriate duty cycle and frequency for reverse iontophoresis. Duty cycle around 95% and frequency of 250 mHz are good for low frequency reverse iontophoresis. Effect of reverse iontophoresis on the skin recovery is observed by monitoring the potential profiles at the end of the process. In all the reverse iontophoresis experiments, safety of the patient is ensured by fixing a compliance voltage level. Finally, Instrumentation to measure the capacitance of biosensors is developed based on frequency domain technique with a sinusoidal input. Accuracy in capacitance measurements is ±5%. Glucose measurement is demonstrated with the developed instrument using a capacitance type biosensor. The obtained results are in good agreement with the standard UV-Visible spectroscopic measurements based on phenol-sulphuric acid assay method.

In the initial stage, the sample preparation was done by using the techniques of Anodic etching and anodic forming processes where a repeated trial and error method of sample preparation headed towards making out a suitable sample set for characterization. After this step, the set of 2 different industrial samples were introduced and anodic oxide forming process was carried out in different electrolytes.    In the sample preparations, 4 different electrolytes were used 15% wt. Ammonium Adiphate, 1.5% wt. Ammonium Phosphate, 7% wt. Boric acid and 15% Penta Borate at different stages for performing the anodic oxide forming process. Minimum forming voltages of 20V to a maximum of 100V was employed in the sample preparation and to overcome the waiting time in forming the etched samples a higher current of 0.5A was used.   After the samples preparation, Electrochemical Impedance spectroscopy was used as a tool for characterising the various groups of samples and for observing the micro structures of various samples, they were fractured and the observed on the cross section by SEM.   After the analysis of the etched samples was made, an attempt to compare the results of the data of these samples to that of the 2 set of industrial samples was made and found that the resultant data wasn’t stable enough to characterize since huge scattering were occurring and whereby the simulation of the CPE circuit for the chosen circuit in the analysis was not possible.   Under the analysis, a randomly chosen industrial sample was also used and the resultant data was utilised in understanding the response of the system to different electrolytes. / Sammanfattning   Avhandlingsarbetet har genomförts på KEMET AB i samarbete med yttekniklaboratoriet vid JTH i syfte att karakterisera den etsade anodiska aluminiumfolien som grundprov med anodisering och etsning för ytbehandling.   I inledningsskedet gjordes provberedningen med användning av teknikerna för anodisk etsning och anodbildande processer där en upprepad provnings- och felmetod för provberedning ledde ut mot att utarbeta en lämplig provuppsättning med avseende på karakterisering. Efter detta steg infördes uppsättningen av 2 olika industriella prover och anodoxidbildande process utfördes i olika elektrolyter.   I provpreparaten användes 4 olika elektrolyter 15 % vikt Ammoniumadiphat, 1,5 vikt% Ammoniumfosfat, 7 vikt% Borsyra och 15 % Penta-borat vid olika steg för utförande av anodoxidbildningsförfarandet. Minimala formningsspänningar på 20V till ett maximum av 100V användes i provframställningen och för att övervinna väntetiden vid bildning av de etsade proven användes en högre ström av 0,5A.   Efter provberedningen användes elektrokemisk impedansspektroskopi som ett verktyg för att karakterisera de olika grupperna av prover och för att observera mikrostrukturerna i olika prover, de bröts och de observerades i tvärsnittet av SEM.   Efter att analysen av de etsade proverna gjordes ett försök att jämföra resultaten av data från dessa prover till den för de två uppsättningarna av industriella prover. Det är konstaterat att de resulterande data inte var stabila nog att karakterisera eftersom stor spridning inträffade och varigenom simuleringen av CPE-kretsen för den valda kretsen i analysen inte var möjlig.   Under analysen användes också ett slumpmässigt valt industriellt prov och de resulterande data användes för att förstå systemets respons till olika elektrolyter.

The work deals with the capacitance measurement of high-voltage PN junctions. The work is divided into theoretical and practical parts. The theoretical part presents insight into the fundamental properties of PN junctions and methods for measuring of the capacitance of PN junctions, primarily by C-V measurement. In the practical part, several kinds of measuring circuits are introduced and a suitable method of measurement is found. The calculations of basic parameters - the width of the base and resistivity are presented and discussed. The results were compared with the values obtained by calculation from the technological parameters of the junction.

This thesis deals with the utilization of new principles of characterization of gate capacitances for sigma-delta modulators. Sigma-delta modulators are the integral part of sigma-delta analog-to-digital converters. The proposed new method is characterized by high resolution and modest requirements for laboratory equipment. It allows characterizing capacitances whose values are within the range which is used in sigma-delta modulators. The thesis contains description of the new method, the analysis of measurement accuracy and experimental results.

This master’s thesis is dealing with possibilities of measurement of inductance by using of accurate capacitance bridge AH 2500E. In metrology there are no appropriate devices available for accurate measurement of inductance. It can be realized by four methods. The newest one is based on T elements, it is not used for this purpose yet and it is practically investigated in CMI Brno. For its introduction to practice it is neccessary to complete computer simulations and analysis of influences affecting measurement. It is also inevitable to examine repeatability of measurement, define methodology of measurement and potential corrections of measured values.