If I want to measure the capacitance of my thin film, then how should I proceed using the The Metrohm Autolab Instrument?
i think you may use EIS Analysis, then you can use software some thing like Zsimwin
this up to my knowledge
To find the specific capacitance I have at first done the Cyclic voltammetry . then I have calculated the total area under the curve . then I have measured the active mass and then I divide the total current by this mass to find the specific current . Now while dividing by scan rate and multiplying by a factor 0.5(to get the Oxidized or reduced area) I get the specific capacitance value.
But how to measure the normal capacitance ?
Dear Gourav, You have to use additional equipment as follows. First of all, you have to add a small alternating voltage to your voltage input of the Autolab, i.e. a sinusoidal signal from a freqency generator. Then you make use of the current output of the autolab, and measure the phase-locked signal 90° to the original ac-voltage - this voltage is a measure of your electrode capacity (correctly speaking, this depends on your system under investigation. You should take into consideration an appropriate equivalent circuit. The 90° phase shift is suitable for a metal in solution, with only the capacity of the electrochemical double layer).
It is useful to apply alternating voltages of about some few mV only, because otherwise all the structures (anodic and cathodic peaks) in your CV-measurements will smear out accordingly.
Good luck, Dirk
I have used an ac signal with r.m.s value of 0.01 mV . and the cell voltage is fixed at 0 Volt and measure the current. Now what procedure I have to follow?
Cyclic voltammetry, FRA potential scan or any other module ? And suppose I have an unknown system. Then how to be sure about the equivalent circuit?
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