Instruction Manual

3.2 VA measurement modes

797 VA Computrace – Software

AC – Alternating Current Voltammetry

General:

AC or Alternating Current voltammetry is primarily suitable

for reversible electrode reactions. It is virtually completely insensi-

tive to irreversible reactions. The AC measurement mode can be set

for the exploratory and determination mode by selecting AC - Al-

ternating current voltammetry

for the Mode parameter in the EX-

PLORATORY SPECIFICATION

or WORKING METHOD SPECIFICA-

TIONS

window.

Description:

For AC voltammetry, a digitally generated sinusoidal alternating

voltage with a small, constant amplitude and a low frequency is

superimposed on a stepwise rising direct voltage ramp. The first or

second harmonic wave of the alternating current component i pro-

duced by the alternating voltage is measured as a function of the

voltage U. The current measurements give peak-shaped (AC1) or

sinusoidal shaped (AC2) curves which can be evaluated using lin-

ear, polynomial, horizontal or exponential baselines.

× √ 2

Amplitude

1 / Frequency

Phase angle

i = Σ

(

i+) / n

Peak voltage

Peak

height

i = Σ

(

i+ - i-) / n

Half-wave voltage

AC1 AC2

Voltage step

Modulation time

Voltage step time

Phase angle