Design and construction of a capacitor sensor with a precise readout system are described in this paper. A variable air-gap capacitive transducer was constructed and for signalmeasurement a successful attempt was made to exploit the capacitance changes in terms of the phase angle of the detected signal. The reported setup makes it possible to detect capacitance changes of the order of 2.5 fF in...

in this research, active capacitance circuit and the feature of negative resistance are analysed in details. also, a new active filter is presented based on active capacitance circuit. for simulations, we used matlab and advanced design system(ads). proposed active filter (rf) is a narrow band filter. the results of simulation shows some aspects of sustainability and low noise feature. the circ...

In this paper, the measurement of capacitance variation, of an on-chip power distribution network (PDN) due to the change of internal states of a CMOS logic circuit, is studied. A state-dependent PDNcapacitance model that explains measurement results will be also proposed. The model is composed of capacitance elements related to MOS transistors, signal and power supply wires, and substrate. Ref...

Recent experiments have shown that nitrogen doping enhances capacitance in carbon electrode supercapacitors. However, a detailed study of the effect of N-doping on capacitance is still lacking. In this paper, we study the doping concentration and the configuration effect on the electric double-layer (EDL) capacitance, quantum capacitance, and total capacitance. It is found that pyridinic and gr...

A capacitance measurement system is developed for the measurement of gas-liquid two-phase flow in glass micro-pipes with inner diameters of 3.96, 2.65 and 1.56 mm, respectively. As a typical flow regime in a micro-pipe two-phase flow system, slug flow is chosen for this investigation. A capacitance sensor is designed and a high-resolution and high-speed capacitance measurement circuit is used t...

we report the enhanced capacitance of the multi-walled carbon nanotubes (mwcnts) after a chemical unzipping process in concentrated sulfuric acid (h2so4) and potassium permanganate (kmno4). the effects of the test duration and temperature were investigated on the unzipping process of the mwcnts to synthesize the graphene oxide nanoribbons. the sem and tem studies were carried out on untreated a...

The formation and disappearance of ice changes will cause the change of its capacitance, we can use this features of air, ice and water has different capacitance under different temperature to measure the ice thickness. The capacitance sensor is designed based on this theory that can measure the ice thickness in the harsh environment more effective. Based on the finite element simulation softwa...

The present paper describes the development of a low cost, highly accurate low capacitance measurement system that can be used over a range of 0 – 400 pF with a resolution of 1 pF. The range of capacitance may be easily altered by a simple resistance or capacitance variation of the measurement circuit. This capacitance measurement system uses quad two-input NAND Schmitt trigger circuit CD4093B ...

Cell membranes behave like electrical capacitors and changes in cell capacitance therefore reflect changes in the cell area. Monitoring capacitance can thus be used to study dynamic cellular phenomenon involving rapid changes in cell surface, such as exo- and/or endocytosis. In this review focus is on the use of capacitance techniques to study exocytosis in human neutrophils. We compare the who...