RANCANGAN ALAT SIKLIK VOLTAMMOGRAM UNTUK APLIKASI PADA PENGUKURAN SEL SUPERKAPASITOR

Abstract

An instrument has been made to measure the voltage and current of supercapacitor cell
using a cyclic voltammetry technique. This instrument consists of a potentiostat and a
signal conditioner. Data processing and analyzing were performed using data acquisition
system of a 12-bit serial ADC type ADS 7476. The ADC circuit a does not have a register
that why it is controlled directly by a microcontroller ATmega8. This circuit was used as
analog data converter of supercapacitor cells into digital data. The output voltage of the
amplifier of supercapacitor cell was acquired by the ADC before it was interfaced to
microcontroller. Data obtained from the ADC was sent by the microcontroller to a
computer with an RS232 serial cable and read using Visual Studio C++. The program
software Visual Studio C++ controled the retrieval of data by selecting a microcontroller
and gain amplifier programmable which was appropriate that the received signal data
acquisition system becomes more optimal. The read data was stored in the database and
then visualized in the form of graphs and tables of voltammogram measurement data. The
tests conducted in this study was a testing of microcontroller, a signal conditioning and
instrumentation overall. Prototypes of this instrument were tested on a modified carbon
electrode with a mixture substance of CNTs10%, PANI 15%, PVDF 5%, and 70% of
activated carbon from cassava. The supercapacitor cell was assembled in the form of coins,
which comminuted of ribbon Stailess steel (316L) as a current collector, a 1M H 2 SO 4
electrolyte and a carbon composite as a working electrode. The measurement of current
obtained a current in the range of -1mA to 0.993 mA at a voltage between 0 Volt to 0.5
Volt from a voltammogram curve. The result obtained was then composed with the
instrument tool of the commercial potentiostat. Error percentage of all measurements was ±
6.05%.