Simple RC Circuits

In the complex plane plots, the arrows show the direction of increasing frequency. Further, Gi = G = R 2, G2 = R.2- Because IS results usually involve capacitance and rarely involve inductance, it has become customary to plot impedance in the -Im (Z), Re (Z) plane rather than the Im (Z), Re (Z) plane, thereby ensur- 

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First of all, membrane capacitance of nerves has a negative frequency dependence below 300 Hz, namely capacitance increases with frequency in this region. This is a behavior which cannot be explained by a simple RC circuit and indicates the presence... 

Rs (Figure 1.22a). The double layer capacitance is represented by the capacitance C, and Rs is the series resistance of the EDLC, also named the equivalent series resistance (ESR). This series resistance shows the nonideal behavior of the system. This resistance is the sum of various ohmic contributions that can be found in the system, such as the electrolyte resistance (ionic contribution), the contact resistance (between the carbon particles, at the current collector/carbon film interface), and the intrinsic resistance of the components (current collectors and carbon). Since the resistivity of the current collectors is low when A1 foils or grids are used, it is generally admitted that the main important contribution to the ESR is the electrolyte resistance (in the bulk and in the porosity of the electrode) and to a smaller extent the current collector/active film contact impedance [25,26], The Nyquist plot related to this simple RC circuit presented in Figure 1.22b shows a vertical line parallel to the imaginary axis. 

Inspection of Figure 4.1.9 suggests that Eq. (20) generates spectra that are similar to those of simple RC circuits. This is indeed the case. In fact, Bonanos and Lilley [1981] showed that the Maxwell-Wagner model is formally identical to the two-element circuit of Figure 4.1.1, but with values of gi, g2, Ci, and C2 that can be expressed as rather complicated functions of Oi, [Pg.218]

The Bode magnitude response of the simple RC circuit will always have the shape shown in Fig. 1.5 and can never exhibit resonance. On the other hand, the capacitor voltage in the series or parallel RLC circuit shown in Fig. 1.6 has the sharp Bode magnitude response shown in Fig. 1.7 when R = 10 L = 1 H, and C = 1 F (frequency scaling can be... 

This identification procedure, based on the experimental analysis of the variation in voltage at the edges of supercapacitor, can be applied to identify the parameters of one or more cells. We can also use this method to identify the parameters of a module of supercapacitors connected in a series and/or in parallel. Thus, a supercapacitor module (irrespective of the number of cells used) can be modeled by a simple RC circuit. 

FIGURE 3.8 Nyquist plot for the indicated simple RC circuit, where — 0.01 Q. 

The influence of Qiis significant in rapid voltametry measurement. The equivalent circuit in Fig. 2 can be regarded as a simple RC circuit with a time constant, t = Qii s, especially when no redox material exists R = oo). In other words, the ctirrent signal response flattens due to the limitation imposed by the time constant dtiring a fast sweep. However, for the microelectrode, z = pa where p is the specific resistance of the solution and a is the radius of the electrode. Hence, unlike with the use of an ordinary electrode, fast sweep is possible. 

Noise elimination -> Noise can be eliminated using either electronic circuits or software procedures. The hardware methods based on simple RC circuits can work well in potentiostats. More complex circuits may have names such as noise filter, noise jammer, or noise killer. Very helpful in protecting the electrochemical cell from external noise is the application of a Faraday box (cage). When smoothing of data is done with the soft-... 

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