Pulsating currents

Pulsating current (PC) consists of a periodic repetition of square pulses. It is similar in shape to RC except for the absence of the anodic component, as is shown in Fig. 4.1b. The PC is characterized by the amplitude of the cathodic current density, ic, the cathodic deposition time, C (on period), and the time interval fp, in which the system relaxes (off period). 

It should be noted that rectified sinusoidal AC, especially half-rectified sinusoidal AC, often termed pulsating current in the literature, shows similar effects to those of the PC [7]. 

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Chopper is a rotating wheel whose function is to break the steady stream of light from the hollow-cathode-lamp into an intermittent light that gives rise to a Pulsating current into the photocell this current is duly amplified and recorded. 

Bawin, S. M. Lin-Liu, S. Adey, W. R. Influence of weak electromagnetically induced pulsating current on Ca binding in isolated cerebral tissue. American Electrochemical Society,... 

Fig. 1 Schematic diagram of experimental apparatus employed for the test of TCE deradation Q) Oxygen tank d)Ozonizer(DOzone stock solution distilled erater Mixing vessel ( )Dual plunger pump without pulsating current (J) syringe pump with high concentration of TCE solution Packed column with an adsorbent Column packed with wet activated carbon for the degradation of exhausted ozone...

Figure 5.35 Striped pyramids of growth on an Ag(lll) crystal face obtained by appUcation of a pulsating current in the standard system Ag(l 11)/AgNOs 5.9, 5.55. Face areaA(iu) = 2 x 10 cm. ...

The discharge appears to occur as though innumerable fine threads were stretched in the discharge space of the tube. The current wave form was observed with the ordinary cathode-ray oscilloscope. The fundamental wave leads the voltage wave by about 90° as shown in Figure 3, and high frequency pulsating currents superpose... 

Figure 1. TEM images of Pt deposited on caibon under different electrodeposition conditions (a) 200 in A cm 2 of peak pulsating current (b) 10 mA cm-2 of DC. Reprinted from Kim et al. 6 with permission from Elsevier.

Fig. 4.1 The current waveforms in EPCR (a) reversing current cycle, (b) pulsating current cycle, and (c) the sinusoidal alternating current superimposed on the direct current (Reprinted from Refs. [7, 12] with kind permission from Springer)...

At a given DC value, three different types of current can be obtained, which can be denoted as follows fp < f c rippling current fp = f c, pulsating current and fp > f(jc, current with an anodic component. The last type is mainly used in plating practice. 

However, an increase in surface coarseness in a deposition using a rectangular pulsating overpotential or pulsating current is only possible during the pulses of current or overpotential [35] and the integral form of Eq. (4.76) can be written as ... 

Popov KI, Maksimovic MD, Ocokoljic BM, Lazarevic BJ (1980) Fundamental aspects of pulsating current metal electrodeposition I the effect of the pulsating current on the surface roughness and the porosity of metal deposits. Surf Technol 11 99-I09... 

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