Flicker effect

For small voltage changes that occur infrequently, flicker is not a serious concern but certainly can be a source of major annoyance. Typically, flicker is caused when a load that requires large currents during startup is initially energized. If the starts are frequent or if the current requirement of the load fluctuates rapidly during each cycle of operation, then flicker effects can be quite pronounced. Examples of loads that could cause light flicker are elevators, arc furnaces, and arc welders. 

GLS lamps do not flicker because the incandescent filament produces a carrying over of the light output as the current reverses. Thus the light remains almost constant and, therefore, the stroboscopic flicker effect is not apparent. 

In a recent study on the ICOR-channel we have compared the effect of NPPB to that of the disulphonate stilbenes (Fig. 2), IAA-94 (Fig. 2) and amidine (Fig. 2). We found that all these compounds induced a flicker-type block. NPPB showed the highest affinity [63]. The results of this study were perplexing inasmuch as compounds which appear to be chemically different, and even possess opposite net charges, exert comparable effects. In further studies on the ICOR channel others and we were able to show that unsaturated fatty acids, bumetanide, the buffer HEPES and even Ca -antagonists such as verapamil inhibited the ICOR channel... 

One study has reported effects on neurobehavioral function in lead-exposed workers at mean PbB levels of 50 pg/dL (Williamson and Teo 1986). Neurobehavioral function was measured using tests that are based on information processing theory in 59 lead workers and 59 controls matched for age, type of job, time on the job, education level, smoking history, and alcohol consumption. Statistically significant decreases in the lead-exposed workers were seen for critical flicker fusion reaction, simple reaction time, tracking speeds, hand steadiness tests, and sensory store memory. Sensory store memory speed showed a low but statistically significant correlation with PbB concentrations. Measurements of neurobehavioral function seemed well chosen, and repeated measures with associated appropriate statistics were used. 

As usual, we will continue in the next chapter we will now start on the derivations of formulas relating to the effects of what we have previously called scintillation noise , and which is also called flicker noise , source noise , and other labels. Basically this... 

Flicker C, Serby M, Ferris SH. (1990). Scopolamine effects on memory, language, visuospatial praxis, and psychomotor speed. Psychopharmacology (Berlin). 100(2) 243-50. 

Schmitt. J.E.J., Riedel, W.J.. Vuurman, E.F.P.M., et al. Modulation of the critical flicker fusion effects of serotonin reuptake inhibitors by concomitant pupillary changes. Psychopharmacology 160, 381-386, 2002. 

Fig. 124 is a representation of Winfield s lucent burner, in which the Liverpool button is applied to an argand gas-burner, and the peculiar form of ohimney causes an external current of air to impinge at a certain angle npon the flame, producing the same effect as the metallic cone in the solar lamp a basket of wire-gauze is fitted into the crutch of tire burner, which moderates the supply of air from below, and prevents the flickering caused by sudden draughts. 

The term power frequency disturbance describes events that are slower and longer lasting compared to electrical transients (see Chapter 3). Power frequency disturbances can last anywhere from one complete cycle to several seconds or even minutes. While the disturbance can be nothing more than an inconvenience manifesting itself as a flickering of lights or bumpy ride in an elevator, in other instances the effects can be harmful to electrical equipment. Typically, the deleterious effects of power frequency disturbances are predominantly felt in the long run, and such disturbances do not result in immediate failure of electrical devices. 

The most common visual side effects are blurring, dimness of vision, flickering or flashing lights, color vision (yellow, green, red, and white), cycloplegia, and diplopia. 

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