We report fabrication and characterization of a new hydrogel-based microsensor for wireless chemical monitoring. The basic device structure is a high-sensitivity capacitive pressure sensor coupled to a stimuli-sensitive hydrogel that is confined between a stiff porous membrane and a thin glass diaphragm. As small molecules pass through the porous membrane, the hydrogel swells and deflects the d...

This paper presents a low-power hybrid thermopneumatic microvalve with an electrostatic hold and integrated valve plate position sensing. This combination of actuators in a single structure enables a high throw and force actuator with low energy consumption, a combination that is difficult to otherwise achieve. The completed 7.5 mm × 10.3 mm × 1.5 mm valve has an open flow rate of 8 sccm at 600...

Ferroelectric thin films offer the possibility of engineering the dielectric response for tunable components in frequency-agile rf and microwave devices. However, this approach often leads to an undesired temperature sensitivity. Compositionally graded ferroelectric films have been explored as a means of redressing this sensitivity, but experimental observations vary depending on geometry and o...

Energy extraction based on capacitive Donnan potential (CDP) is a recently suggested technique for sustainable power generation. CDP combines the use of ion-exchange membranes and porous carbon electrodes to convert the Gibbs free energy of mixing sea and river water into electric work. The electrodes geometry has a relevant impact on internal resistance and overall performance in CDP. In this ...

Silicon Laboratories' capacitive sensing techniques are compatible with external ESD protection methods. Designers should be aware of parasitic parameters in these circuits which affect capacitive sensing performance when implementing these protection methods. While most of the methods affect sensing performance in some way, in almost all cases an acceptable balance between performance, protect...

A dilatometer cell that can detect sub angstrom changes in the length of solid specimens in the temperature range 5 K<T<350 K is described. It is constructed entirely from fused quartz (silica). This is a capacitive-based technique, where the spacing between two metallized plates allows detection of changes in length. It is also a relative measurement in the sense that the capacitor plate spaci...

Fluorescence lifetime imaging microscopy (FLIM) has allowed scientists to discern information about the chemical properties of biological processes and has become a vital tool in the life sciences and medical research communities. Measuring the spatial lifetime distribution of the fluorophores as well as the intensity distribution enables users to discern vital information about the chemical en...

Contactless conductivity detection was carried out on a planar electrophoresis device by capacitive coupling using an ac excitation voltage of 500 V(p-p) and a frequency of 100 kHz. It was possible to carry out detection in this way through a cover plate of 1 mm thickness. Better sensitivity is obtained, however, by placing the electrodes into troughs that allow tighter coupling to the separati...

This article presents a software tool to automatically generate the mathematical model of capacitive MEMS gyroscopes in a symbolic form. After describing the operational principle of a specific one-axis gyroscope with capacitive drive actuators and capacitive sensors, a mathematical concept is presented that allows for the systematic description of a certain class of capacitive MEMS gyroscopes....

In a capacitive power transfer (CPT) system, the coupling capacitance formed between plates is very small only in pF or nF range, which leads to high voltage stress among during energy transmission, increases risk of an electrical breakdown coupled plates. To solve this problem, novel dual-frequency CPT system proposed paper, uses “peak clipping” effect caused by superposition fundamental wave ...