Square wave excitation

In addition we have to take into consideration the conservation of charge. The charge balance equation reads 

Therefore, from (3.10.17) we obtain the following equation for the curvature 

T is the decay time for curvature, and rj is an effective viscosity coefficient given by 

Equations (3.10.14) and (3.10.18) are two coupled equations which cannot be solved analytically for any general value of Ej t) since y itself depends on E and t. However for a square wave 

In this case y remains constant in any half-period and the solutions are simpler and enable a physical interpretation of many of the observed phenomena. If the solutions are taken in the form  

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Figure 23-21 Generation of a square-wave voltammetry excitation signal. The staircase signal in (a) is added to the pulse train in (b) to give the square-wave excitation signal in (c). The current response At is equal to the cuirent at potential I minus that at potential 2.

Ait us assume that a square-wave excitation potential /i jppi is applied to the working electrode for a period of lime I as shown in Figure 25-9a. Let us further assume lhat L pp, is large enough that the ratio Cp/c" in Hqualion 25-3 is 1(XX) or greater. Under this condition, the concentration of A at the electrode surface is. for... 

Fig. 3.10.5. Threshold voltage versus frequency for MBBA. Sample thickness 50/ m. Open circles sinusoidal excitation triangles square wave excitation. (After the Orsay Liquid Crystals Group. )...

Fig. 3.10.8. Time dependence of the charge q and the curvature ij/ over one period of the square wave excitation, (a) Conduction regime (cot < 1, T > r). The charges oscillate but the domains are stationary, (b) Dielectric regime (cot P I, T< t). The charges are stationary and the domains oscillate. (After Smith et...

Fig.II.3.1 Scheme of the square-wave excitation signal. E cc starting potential to delay time sw SW amplitude AE scan increment r SW period if forward current /b backward current, and ( ) points where they were sampled...

Figure 8.31 Simple arrangement for time domain measurements and the corresponding waveforms when using a square wave excitation. VappHed is the stimulus and voltage across the MUT (Vmut) the voltage response. is a measuring resistor. T is the duration of one period. Vj=o is the voltage immediately after a positive step and Vy/2 the voltage immediately before a...

We will now discuss the simplest equivalent circuits mimicking the immittance found in tissue measurements. In this section, the R-C components are considered ideal that is, frequency independent and linear. Immittance values are examined with sine waves, relaxation times with step functions. A sine wave excitation results in a sine wave response. A square wave excitation results in a single exponential response with a simple R-C combination. 

The threshold conditions Eth, Wth are found from (5.61) by the same procedure as for (5.39). For a square wave excitation with frequency / and amplitude E... 

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