Time sinusoidal current

The Electromagnetic Fields Created by Time-Sinusoidal Current... 

Figure 8.8 In impedance analysis, a sinusoidally varying potential V is applied across a sample, and the time-dependent current / is measured as a function of the frequency co. The current induced in response to the varying potential will be out of phase, by a time lag 9, and of different magnitude.

The analyser applies a tiny voltage V across the sample (perhaps superimposed on a pre-set or offset voltage). The magnitude ofW varies with time since it is sinusoidedly modulated. The analyser measures the respective time-dependent currents I, and hence calculates Z and the time lag 9 experienced between the current and voltage. 

For sinusoidal currents with an rms value 7rms and a current flow time A t (at least several half periods) this equation can be simplified ... 

When a sinusoidal voltage signal E = E sin(o)t) is applied to a cell, the result is a sinusoidal current signal of the same frequency but displaced somewhat in time, i = i sin((Dt + (p), namely, having a... 

If the field is time-sinusoidal, the source current is of the form... 

Source Currents of Time-Sinusoidal Polarized Field... 

In the presence of only resistive components, the ac waveform is defined only by its magnitudes. The current response to a potential sinusoidal wave, as shown in Fig. 5.19, indicates that the potential and the current traces differ not only in magnitude but also in phase. The time-dependent current response I t) of an electrode interface is a function of sinusoidal ac. Potential signal V t) is given in Eq. (5.41a) by frequency (a ) dependent impedance Z(a ) [68] ... 

When a potential which is time-dependent in a sinusoidal manner, i.e., dE sin cot, where dE < 5 mV, is applied across an electrochemical cell, a sinusoidal current zli sin (cot -f cp) will flow as a consequence. One can define an impedance, Z, as having a magnitude given by... 

V is the stimulus frequency, Gq the amplitude.of sinusoidal current and the time between the frequency response of the cell and the applied stimulus) eq.-3- integrates to... 

Membrane impedance measurements can be achieved by using various methods. One possible approach consists to apply a sinusoidal current or voltage signal of a given frequency and to determine the corresponding voltage or current response by means of a lock-in amplifier or a vector impedance meter. This procedure must be repeated for every frequency of interest, which makes the measurements quite time consuming. Two... 

In an alternating current system the voltage and current components travel in the shape of a sinusoidal waveform (Figure 17.9) and oscillate through their natural zeros, 100 times a second for a 50 Hz system. 

Fig. 5.12. Stress versus time responses (measured currents) for (a) fee 28.5-at. % Ni above 2.5 GPa (25 kbar), (b) below 2.5 GPa, and (c) for bcc 28.5-at. % Ni, reveal substantial differences in mechanical response. Such records at different input stresses are used to determine the various stress-volume relationships (after Graham et al. [67G01]). Time increases from right to left. Timing waves (upper sinusoidal signal) are 10 MHz.

Rather high charging currents cross the electrode when a variable potential component is applied. Therefore, to reduce the influence of these currents in the case of rectangular pulses, the measurements are made at a specific time after the potential change, when the charging current has decreased drastically. In the case of sinusoidal superimposed currents, one uses another device based on the fact that the... 

Phase-modulation immunoassay measurements are made with sinusoidally modulated light. Since the emission is a forced response to the excitation, the emitted light has the same periodicity as the excitation. Due to the time lag between absorption and emission, the emission is delayed in comparison with the excitation. The time delay between the zero crossing of one period of the excitation and of the emission is measured as the phase angle (Figure 14.11). The emission is also demodulated, due to a decrease in the alternating current (AC) component of the AC to direct current (DC) ratio. 

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