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Better Amplitude Accuracy with MFLI Analog Adder

07.03.2016

HF Output Add

Many lock-in applications use a drive signal consisting of a small AC excitation voltage and larger DC offset voltage, for example differential conductance (dI/dV) measurements. Users of the MFLI Lock-in amplifier have the choice between two methods to generate such a signal: using the analog adder ("Add"), or using digital...

Eddy current testing with the MFLI Lock-in Amplifier

05.08.2015

Eddy current

This blog describes a method to detect material defects. Eddy current measurements are used for non-destructive material testing (NDT). An alternating magnetic field is penetrating a sample. The material defect is detected by a phase shift. In the first part of the blog the experimental setup is described and in...

Achieving High Data Transfer Rates with the UHFLI

07.07.2015

Scope Streaming Schematic

Introduction The UHFLI Lock-in amplifier features the smallest time constant on the market, making it an excellent instrument for fast measurements like in imaging applications. The UHFLI can provide demodulated data at a bandwidth of up to 5.2 MHz and sampled at up to 28 MSa/s. That stream of data...

Pass/Fail Tests for Failure Analysis

08.06.2015

Pass/Fail Graph

For quality control in manufacturing process, there are many ways to tests for transistors or other component failure, but for high throughput verification usually simple Pass/Fail tests are required. Since devices are tested for various functions, different tests need to be performed in this pass or fail mode. The basic...

Deep Level Transient Spectroscopy Using HF2LI Lock-in Amplifier

23.05.2015

DLTS vs Temperature

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 (either beneficial or detrimental) role in determining the suitability...

Demodulating down to DC with HF2LI

18.11.2014

DC Demod

Many of our customers use the possibility to measure DC voltage and current, together with an ac signal by setting the demodulation frequency ω=0. The measured value is seemingly incorrect as you need to divide the obtained rms value with the factor of √2 to get the actual signal amplitude...

Detecting a small fraction of impedance changes with improved sensitivity

16.09.2014

Theoretical Schematic

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 applications, for example. The second type is of course...

Basic vector network analyzer (VNA) measurements using the UHFLI

03.07.2014

Reflection

Introduction This article describes how to measure reflection and transmission coefficients using a Zurich Instruments UHFLI Lock-in Amplifier and a directional coupler. Network analysis is a commonly performed in RF measurement. A network analyzer is an instrument that measures the network parameters of electrical circuits. Circuits that can be analyzed...

How to Achieve More Stable Z-feedback in FM-AFM Mode

15.05.2014

Choice of set point

The challenge with FM-AFM mode (or NC-AFM for Non-Contact Atomic Force Microscopy) is that tip-sample interaction can be either attractive (negative frequency shift, -df) or repulsive (positive frequency shift, +df) which leads to different parameter settings for the Z feedback loop with, respectively, either a positive or negative slope. For...

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

08.01.2014

Impedance Frequencies

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 multi-frequency capability of the instrument enable microfluidics researchers not...

Ring-Down Method for Rapid Determination of High Q-factor Resonators

18.12.2013

Ring down

With the miniaturization of circuits and components such as MEMS and now also NEMS (Nano-Electro-Mechanical Systems), the variety and quality of macro-fabricated devices have dramatically increased, leading to packaged or embedded systems with particularly sensitive electromechanical properties. The basic properties, such as resonance frequencies, Q-factor and dissipative power requires more...

Tracking Resonance Frequency without Phase: the DFRT Method

18.10.2013

PFM Image

For high Q-factor resonator (> 500), it is a common method for SPM application to use a Phase Locked Loop (PLL) to track the change in cantilever frequency: the high phase sensitivity at 90° guarantees accurate measurements and stable PID feedback on the driving oscillator. This is of particular interest...

Optimize Your HF2TA Transimpedance Amplifier Settings

24.05.2013

HF2TA Diagram

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 gain drop-down list in ziControl.) However, there are other pitfalls...

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