Frequency response analyzer
A frequency response analyzer is a device that measures the response signal of an electrochemical system to an applied potential including a small superimposed sinusoidal waveform. In electrochemical research a frequency response analyzer (FRA) is used for electrochemical impedance spectroscopy (EIS).
In the past, a frequency response analyzer was just the device that generated the signal and recorded the response. In order to carry out an entire electrochemical experiment, an additional potentiostat was needed (see figure 3). The potentiostat connected the generated frequency waves with an electrochemical cell and recorded the response.
Nowadays, potentiostats are usually equipped with a frequency response analyzer so that you only need one device for the entire experimental setup. If you need a frequency response analyzer, the purchase of a PalmSens4 portable potentiostat is your best choice.
How does a frequency response analyzer work?
A frequency response analyzer generates a signal with a certain frequency and a certain amplitude. The response of the electrochemical system to this signal is also a periodic signal. The frequency response analyzer measures both amplitudes and the phase shift (the time difference between the transmitted and received signal, see figure 1).
In electrochemical research, a frequency response analyzer is used to measure the electric current response as reaction to an applied potential wave. The magnitude allows calculating the impedance. You can do this for example with our PalmSens4 potentiostat/galvanostat that has EIS capabilities.
Figure 2: Bode plot of a carbon SPE (IS-1) in potassium ferricyanide solution.
This measurement is repeated at different frequencies. In a graph the researcher can see how the different frequencies influence a certain system. This information is useful, for example, when testing batteries or coatings.
At low frequencies only slow changes will occur; chemical processes are responsible for the major contribution. At high frequencies, physical properties will influence the signal (see figure 2).
How is a Frequency Response Analyzer applied?
In electrochemical investigations, a frequency response analyzer can be used to demonstrate the presence of a given substance in a liquid, for example the presence of a certain DNA or protein using a dedicated biosensor. It can also be used to investigate the resilience of materials and interfaces, such as the durability of a certain paint layer or specialized coating. Read more about this on our PalmSens Corrosion website.
Advantages of a Frequency Response Analyzer
A major advantage is the predictive value of tests that are made using a frequency response analyzer. A FRA test (i.e. a frequency scan) does not take much time at all, while testing for corrosive properties by salt spray tests takes a very long time.
Frequency Response Analyzer sensors
Many materials can be analyzed with a frequency response analyzer. In corrosion research the corroding materials are connected directly to the frequency response analyzer. This is similar in fuel cell or battery research. In analytical chemistry, a number of sensors were developed that only change their resistance in contact with specific substances. Also modern biosensors are investigated using electrochemical impedance spectroscopy. Check out our sensors here.
Frequency Response Analyzer software
Such a frequency response analyzer is of no use without associated software. The PalmSens4 includes its own easy-to-use software, which allows you to run experiments smoothly and then use the equivalent circuit fitting to get the all required information out of your data. If you prefer you can also use your own or third party spreadsheet software for creating charts.
Frequency Response Analyzer prices
Frequency response analyzers tend to be very expensive, PalmSens has succeeded in developing a Frequency Response Analyzer that is portable, affordable and with outstanding specifications.