Browsing Bergen Open Research Archive by Author "Helseth, Lars Egil"
Now showing items 1-9 of 9
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Comparison of methods for finding the capacitance of a supercapacitor
Helseth, Lars Egil (Journal article; Peer reviewed, 2021)A carbon-based supercapacitor is usually associated with a capacitance such that the user can access its ability to store electrical charge. Three different measurement methods or variations thereof are typically employed ... -
Harvesting energy from light and water droplets by covering photovoltaic cells with transparent polymers
Helseth, Lars Egil (Journal article; Peer reviewed, 2021)Energy harvesting of sunlight is often done using photovoltaic cells covered by a protective layer of polymer or glass. Currently, this layer does not have any other function than being transparent and protective, but its ... -
The influence of microscale surface roughness on water-droplet contact electrification
Helseth, Lars Egil (Peer reviewed; Journal article, 2019)When water comes in contact with a hydrophobic fluoropolymer, a triboelectric charge tends to form on the surface. Here, it is investigated how the triboelectric charge formed upon contact with water drops depends on the ... -
Influence of Salt Concentration on Charge Transfer When a Water Front Moves across a Junction between a Hydrophobic Dielectric and a Metal Electrode
Helseth, Lars Egil (Journal article; Peer reviewed, 2020)An energy-harvesting device based on water moving across the junction between a hydrophobic dielectric and a metal electrode is demonstrated. The charge transfer due to contact electrification as the junction is dipped ... -
Modelling supercapacitors using a dynamic equivalent circuit with a distribution of relaxation times
Helseth, Lars Egil (Peer reviewed; Journal article, 2019)Supercapacitors are often modelled using electrical equivalent circuits with a limited number of branches. However, the limited number of branches often cannot explain long-term dynamics, and one therefore has to resort ... -
On the accuracy of an interdigital electrostatic position sensor
Helseth, Lars Egil (Journal article; Peer reviewed, 2020)In this work the induced voltage in an interdigital electrode when swept by a finite, triboelectrically charged dielectric surface is investigated. Finite element modelling fits well with the measured voltage as a function ... -
The self-discharging of supercapacitors interpreted in terms of a distribution of rate constants
Helseth, Lars Egil (Journal article; Peer reviewed, 2021)Supercapacitors are prone to self-discharging, which is most often measured as a voltage decrease with time under open circuit conditions. It is of substantial interest to find simple and general methods to extract information ... -
Triboelectric proximity and contact detection using soft planar spiral electrodes
Helseth, Lars Egil (Peer reviewed; Journal article, 2019-08-02)In this study, planar spiral electrodes for triboelectric contact and proximity detection are investigated. The spiral electrodes are created using liquid metal in a soft elastomer in order to make the sensor flexible and ... -
A water droplet-powered sensor based on charge transfer to a flow-through front surface electrode
Helseth, Lars Egil (Journal article; Peer reviewed, 2020)A water droplet sensor based on a flow-through front surface electrode is demonstrated. It is shown that a triboelectric nanogenerator based on a metal-dielectric junction can be utilized to construct simple, self-powered ...