Posts by James Wei

Permittivity Measurement with HF2IS Impedance Spectroscope

on 17.11.2015 at 12:47 by James Wei on Blog of James Wei
Introduction Dielectric spectroscopy is a form of impedance spectroscopy where the dielectric properties i.e. permittivity of a medium is characterized as a function of frequency. This technique allows us to evaluate the energy storage and dissipation properties of a capacitor […]

Characterization of Dye-Sensitized Solar Cell Impedance at Low Frequencies with HF2IS Impedance Spectroscope

on 03.07.2015 at 12:29 by James Wei on Blog of James Wei
Co-author and main contributor: Dr. Antonio Braga Introduction The electrical impedance spectroscopy (EIS) technique is used to characterize the physical-chemical processes of the dye-sensitized solar cells (DSSC) using different types of metal oxides semiconductors, dyes or electrolytes [1]. The EIS […]

Deep Level Transient Spectroscopy Using HF2LI Lock-in Amplifier

on 23.05.2015 at 10:58 by James Wei on Blog of James Wei
Co-author and main contributor: Dr. Antonio Braga Introduction A very small concentration of lattice point defects, or simply defects, such as vacancies, impurities, dislocations, grain boundaries or cavities, are responsible for creating many different properties in semiconductors. Defects play a crucial […]

Measuring the I-V Characteristic of PN Junction Devices with HF2LI Lock-in Amplifier

on 13.05.2015 at 09:24 by James Wei on Blog of James Wei
Co-author and main contributor: Dr. Antonio Braga Introduction The p-n junction is the fundamental building block of semiconductor material electronics device such as transistors, diodes, sensors, laser, light emitting diodes, as well as solar cells. If one wants to know […]

Using HF2IS Impedance Spectroscope as a DC Impedance Meter

on 18.11.2014 at 11:11 by James Wei on Blog of James Wei
Up until now, the blogs related to impedance measurement are mostly related to how to setup a measurement and optimize the ac frequency sweeps. As a matter of fact, the HF2IS Impedance Spectroscope can also be used as a dc […]

Detecting a small fraction of impedance changes with improved sensitivity

on 16.09.2014 at 13:54 by James Wei on Blog of James Wei
Introduction There are normally two types of impedance measurement. The first type is the dynamic impedance measurement where impedance can change rapidly over time. This is the case in electrical impedance spectroscopy (EIS) in microfluidics for cell counting and cell discrimination […]

Processing Data in Different Applications with LabOne Net Link

on 01.07.2014 at 14:01 by James Wei on Blog of James Wei
Many HF2 and UHF users take advantage of the API provided by Zurich Instruments to program in Matlab, Python, Labview and C to record data from the HF2 and UHF devices. Both HF2 and UHF also provide the possibility to stream […]

Reduce Ground Disturbances when using HF2TA Transimpedance Amplifier in a Measurement Setup

on 26.02.2014 at 18:13 by James Wei on Blog of James Wei
Ground loops can potentially pose a serious problem in many measurement setups. Due to the multiple connections to and from the HF2TA current amplifier and other external components, several ground loop related issues can pop up in the signal being […]

Taking Your Microfluidics EIS Measurement to the Ultra-High Frequency Domain

on 08.01.2014 at 13:28 by James Wei on Blog of James Wei
Introduction The HF2IS Impedance Spectroscope from Zurich Instruments is a versatile tool suitable for label-free electrical impedance spectroscopy (EIS) of single cells in the domain of cell counting and discrimination. The high frequency range, from DC to 50 MHz, and the […]

Square Wave and Sawtooth Wave Generation with HF2LI Lock-in Amplifier

on 13.12.2013 at 09:52 by James Wei on Blog of James Wei
Normally, HF2LI users only generate sinusoidal waveforms with the HF2LI lock-in amplifiers. The HF2LI can also generate square and sawtooth waves, although this is not a supported feature. This blog will go through the setups necessary for doing just that. […]

Express EIS Platform for Microfluidics

on 11.10.2013 at 14:07 by James Wei on Blog of James Wei
This blog is aimed for those interested in knowing more about setting up an electrical impedance spectroscopy (EIS) based on a microfluidic setup. In 2012 Zurich Instruments joined forces with Fluigent and Micronit by proposing an Electrical Impedance Spectrosocpy platform (EISP) […]

Using HF2IS Impedance Spectroscope for FRA, 2-Terminal and 4-Terminal Measurements

on 19.09.2013 at 14:14 by James Wei on Blog of James Wei
Often there are questions from our HF2IS Impedance Spectroscope users on how to configure the HF2IS for frequency response analysis (FRA), 2-Terminal impedance measurement, or 4-Terminal impedance measurement. This short blog will clarify the proper physical connections as well as […]

Guide to Tuning the HF2LI-PID Controllers

on 17.09.2013 at 10:54 by James Wei on Blog of James Wei
On the Zurich Instruments website, there are a few advanced examples of using HF2LI-PID controllers in different feedback control applications. However, I often get questions from first time users on how to properly tune the PID gain parameters. I am […]

Remote Access to HF2 Instruments on the LAN

on 07.06.2013 at 08:56 by James Wei on Blog of James Wei
As explained in the HF2 User Manual, users can configure in ziControl to connect to any ziServer host on the LAN i.e. remote client access to HF2 Instrument. This blog will sum up an easy two-steps procedure to do exactly […]

Optimize Your HF2TA Transimpedance Amplifier Settings

on 24.05.2013 at 11:43 by James Wei on Blog of James Wei
Users of the HF2TA transimpedance amplifier should always be aware of the trade-off between the transimpedance gain and the 3-dB roll-off bandwidth of the amplifier. (Hint: Since the HF2 software release 12.08, the bandwidth is also specified in the HF2TA […]

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