How to Add FRA Capabilities (EIS) to your Potentiostat/Galvanostat

EIS (Electrochemical Impedance Spectroscopy) is an electrochemical testing technique used to study corrosion, coatings, batteries, semiconductors and more. There are a variety of methods, with advantages over dc techniques.

EIS requires a Frequency Response Analyser (FRA). All VersaSTAT potentiostat/galvanostats from Princeton Applied Research (PAR) include an FRA which can be activated easily.

An upgrade offer is currently available, giving you free data fitting software when you activate the FRA on your VersaSTAT. There’s also a trade-in offer if you’re thinking of swapping your current PAR or Solartron instrument for a newer system.

Blue Scientific is the official distributor for Princeton Applied Research in the UK, Ireland and Nordic region (Norway, Sweden, Iceland, Finland, Denmark). For more information or quotes, please get in touch.

Princeton Applied Research instruments

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 Contact us on +44 (0)1223 422 269 or


Electrochemical Impedance Spectroscopy (EIS)

EIS is an electrochemical testing technique that gives you accurate kinetic and mechanistic information. It’s fast, non-destructive and can be used to measure electrochemical processes at various timescales.

With EIS you can answer questions such as:

  • What is the equivalent series resistance (ESR) of my device?
  • What is the state-of-charge of my battery?
  • What is the solution resistance of my cell? What is my rate of electron transfer?
  • Is my coating failing? Is the inhibitor effective?

What can you Study?

There’s a variety of techniques and output formats, used to study these electrochemical phenomena:


  • Rate determination
  • Inhibitors and coatings
  • Passive layer investigations


  • Dielectric measurements
  • Corrosion protection


  • State-of-charge
  • Materials selection
  • Electrode design

Battery testing with EIS


  • Bath formulation
  • Surface pre-treatment
  • Deposition mechanisms
  • Deposit characterisation

Electro-Organic Synthesis

  • Adsorption/desorption
  • Reaction mechanisms


  • Photovoltaic work
  • Dopant distributions

Advantages of EIS

EIS has three main advantages over dc techniques:

  1. Small Amplitude
    EIS uses very small excitation amplitudes, usually in the region of 5 – 10 mV peak-to-peak. Excitation waveforms at this amplitude cause only minimal perturbation of the electrochemical test system, which means that the margin for error is much smaller and results are more accurate and reliable.
  2. Mechanism Studies
    Electrochemical impedance experiments provide data about both electrode capacitance and charge-transfer kinetics, which gives you valuable mechanistic information.
  3. Measurement Accuracy
    There is no potential scanning, which means that measurements can be made in low conductivity solutions. In these cases dc techniques would have significant potential-control errors. EIS can even be used to calculate the uncompensated resistance of an electrochemical cell.

Application note: Theory of EIS and how it works 


To perform EIS experiments you need a Frequency Response Analyser (FRA). This is included in all systems in the VersaSTAT range from Princeton Applied Research (Ametek). The FRA can be activated easily and used to run impedance experiments. There is no downtime and the upgrade can be performed by you in your own laboratory.

VersaSTAT potentiostats

VersaSTAT 3

  • 650 mA current maximum
  • High current booster options up to 20 A
  • FRA option for EIS measurements from 10 µHz to 1 MHz
  • Easy to use VersaStudio software included

More info…

VersaSTAT 3F

  • 650 mA current maximum
  • Capable of “floating” operation with filters for enhanced signal to noise ratio
  • Specialized float mode filters for enhanced signal to noise ratio
  • FRA option for EIS
  • Easy to use VersaStudio Software included

More info…

VersaSTAT 4

  • 1 A current maximum (20A boosted)
  • 120 fA current resolution
  • 2 µsec time base
  • FRA option for EIS measurements from 10 µHz – 1 MHz
  • Easy to use VersaStudio software included

More info…

VersaSTAT Upgrade Offer

If you already have a VersaSTAT and would like to add FRA capabilities, an upgrade offer is currently available. Get a free copy of Ametek’s ZSimpWin impedance data processing software when you upgrade:

  • Integrates with VersaStudio
  • Straightforward, versatile equivalent circuit model fitting
  • Automatic analysis with minimal user input
  • Set up batches of multiple jobs

For more information about the offer please get in touch.

Trade-in Offer

Thinking of updating your electrochemical testing system? There’s also a trade-in offer: swap your current instrument from Princeton Applied Research or Solartron Analytical for a discount on a new system.

This includes the latest instruments:

Contact us for more details and for advice on which new system would work best for you.

 Contact us on +44 (0)1223 422 269 or

Princeton Applied Research instruments

More posts about EIS