attached
The main objective of this project is to develop a low cost potetiostat t0
monitor redox processes where the instrument can be later optimized to meet
the needs of clients from industry.The developed system consist of three main
modules namely, user interface, triangular voltage generator, and current to'
voltage converter. User inputs of scanning voltage range and scanning rate can
be input through the user interface, Triangular voltage generator consists of
four sub circuits such as Atmega 328p microcontroller based B-bit step counter,
digital to analog convertor (PCF 8591 8-bit DAC), difference amplifier and
inverting summing amplifier. This module outputs triangular voltage in the
range of -2.5 V to +2.5 V at a user given rate where it connects to the working
electrode of the three-electrode system. Current to voltage converter takes
input from counter electrode of the three electrode system' The output voltage
of this circuitry inputs to the microcontroller for real time data acquisition.
Overall nine operational amplifiers were used to construct the proposed circuit
and it is powered with 1,2 V DC power supply.The system constructed in this
work can operate within the voltage range of -2.5 V to 2.5 V, where the user
can select the desired scan rate and input parameters through a personal
computer interfaced to the instrument for cyclic voltammetry. The current
range measured using this system is 25 pA-2.5 mA, Performance of this system
is compared with a commercially available potentiostat using K3Fe(CN)6 and
FeCl3 solutions, The three electrode system reported here consists of a Ag/AgCl
reference electrode, a carbon working electrode, and a Pt working electrode
with aqueous KCI aS the electrolyte. Results are in agreement with
commercia lly available resea rch grade potentiostats.
