Versus Current

SAFETY NOTE Whenever anything is plugged into the 120 V ac wall socket, as it will be in the next experiment, it would be best to have it go through a ground fault interrupter. Even the small 12 V transformer could possibly have an internal short circuit from a primary wire to the metal case, or to one of the 

In this experiment, plug in the transformer and use its 12 V secondary instead of the bahery. With the X versus Y type of scope display, a continuous oval pattern is observed, which is called a Lissajous figure, named after an early scientist. The vertical VOLTS/DIV knobs, and also their smaller VARIABLE knobs, can be adjusted to other settings such as 5V / div for X and 20 mV / div for Y, in order to make the scope pattern become nearly a perfect circle. 

Switching the MODE from CH2 to DUAL and TIME/DIV from X-Y to 20 ms will provide a two-wave display, much like the right-hand side of Fig. 9.7. (Unplug the BNCs before the transformer, to avoid an inductive kick.) 

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Typical light output versus current (L—I) and efficiency curves for double heterostmcture TS AlGaAs LEDs lamps are shown in Eigure 8. The ir LED (Eig. 8a) is typically used for wireless communications appHcations. As a result, the light output is measured in radiometric units (mW) and the efficiencies of interest are the external quantum efficiency (rj y. = C y., photons out/electrons in) and power efficiency. As a result of the direct band gap... 

Graphs of operating potential versus current density are called polarization curves, which reflect the degree of perfection that any particular fuel cell technology has attained. High cell operating potentials are the result of many years of materials optimization. Actual polarization curves will be shown below for several types of fuel cell. 

Polarization probes rely on the relationship of the applied potential to the output current per unit area (current density). The slope of applied potential versus current density extrapolated through the origin, yields the polarization resistance Rp, which can be related to the corrosion rate. 

ASTM G59, Standard Prac tice for Conducting Potentiodynamic Polarization Resistance Measurements, provides instructions for the graphical plotting of data (from tests conducted using the above-noted ASTM Standard G103) as the hnear potential versus current density, from which the polarization resistance can be found. 

Polarisation Resistance slope of the linear plot of overpotential versus current density measured at potentials close to the corrosion potential, or the tangent of such a curve at the corrosion potential if the plot is not linear. If a small change in potential, A , gives rise to a change in current density. A/, then the polarisation resistance is / p(Q m ) = AE/Ai. 

Figure 10. Rate performance plot of % capacity versus current density for Li/11.7%Cu-graphite cell at 50 °C in 1 1 EC.DEC (1 MLiPF6 LP-40 and literature values ofLi/ 3.09% Cu (electroless) on graphite cell and Li/graphite cell (no Cu) at room-temperature in 20% PC...

FIGURE 2.19 Anode overpotential versus current density in hydrogen with different concentration of H20. The plot at the bottom is the enlarged part for the polarization in region I. (From Jiang, S.P. and Badwal, S.P.S., J. Electrochem. Soc., 144 3777-3784, 1997. Reproduced by permission of ECS-The Electrochemical Society.)... 

Fuel cell vehicles, 73 800-801 Fuel cell voltage equation, 72 208 Fuel cell voltages, 72 206-209 versus current densities, 72 208 Fuel cooling, in pressurized water reactors, 77 544... 

For ordinary electrode reactions, as is described in Sec. 7.2.2, the kinetics is linear (a linear afiinity versus reaction rate relationship and a linear potential versus current relationship) in the vicinity of equilibrium potential. q and... 

Fig. 10-28. Polarization curves for cell reactions of photoelectrolytic decomposition of water at a photoezcited n-type anode and at a metal cathode solid curve M = cathodic polarization curve of hydrogen evolution at metal cathode solid curve n-SC = anodic polarization curve of oxygen evolution at photoezcited n-type anode (Fermi level versus current curve) dashed curve p-SC = quasi-Fermi level of interfadal holes as a ftmction of anodic reaction current at photoezcited n-type anode (anodic polarization curve r re-sented by interfacial hole level) = electrode potential of two operating electrodes in a photoelectrolytic cell p. sc = inverse overvoltage of generation and transport ofphotoezcited holes in an n-type anode.

The general voltage versus current density relation is ... 

Cell voltage versus current density of the electrode with a Nation content of 1.0 mg/cm on the surface and various Nation contents inside the catalyst layer. (Reproduced from Lee, D. and Huang, S. International Journal of Hydrogen Energy 2008 33 2790-2794. With permission from the International Association of Hydrogen Energy.)... 

Plot of fuel cell voltage versus current density showing the transition between two principal states of operation corresponding to ideally wetted conditions with primary pores filled and secondary pores available for gas diffusion and fully flooded conditions. In the depicted case, the transition involves a bistability. 

With the best electrocatalyst, that is, Pt-Sn (90 10)/XC72, the effect of temperature on the cell voltage E and power density P versus current density j characteristics is shovm in Figure 1.14. It appears clearly that increasing the temperature greatly increases the performance of the cell, from a maximum power density close to 5 mWcm at 50 ° C to 25 mW cm at 110 ° C, that is, five times higher. 

Fig. 4 Potential versus current forthe reversible O2/H2O system on a bright platinum surface (Reproduced with permission from Ref 44).

First of all, the mathematical background will be developed for the case of a simple electrode reaction O + n e = R. In this treatment, contrasts like potential versus current perturbation, large amplitude versus small amplitude, and single step versus periodical perturbation are emphasized. While discussing these principles, the most common methods derived from them will be briefly mentioned. On the other hand, it will be shown that, by virtue of the method of Laplace transformation, these methods have much in common and contain, in principle, the same information if the detected cell response is of the same order. 

Fig. 16. Cathodic overpotential versus current density for the cells LaCoOj/protector/YSZ and LaCoOj/YSZ in air at 800 °C.

Fig. 17. Cathodic overpotential versus current density for different annealing periods at 1000 °C for the cell LaCoO3/La0 9Bao,AIO2.95/YSZ in air at 800 °C. The variation of overpotential at the current density of 100mA/cm2 with the preannealing period is also shown. A 12 h, o 36 h, A 48 h, 60 h. From ref. [75]. Reprinted by permission of the American Ceramic Society.

Fig. 29. Anodic polarization versus current density in metal-YSZ cell at 800 °C. Pt, Au, Ru, Co, Fe, Ni, Mn, Pd. From ref. [91].

Figure 6. Charge storage utilization versus current density at —20°C for various initial water contents and electrode thickness, (reproduced with permission from Thompson et al.10)...

Figure 7.8 shows the diagram of voltage versus current. As can be seen, the new designs, HPD5 and Delta9, both present an increase in current density with respect to the traditional tubular configuration. This allows lower production costs. 

The /3-diketonate [Nd(dbm)3bath] (see figs. 41 and 117) has a photoluminescence quantum efficiency of 0.33% in dmso-7r, solution at a 1 mM concentration. It has been introduced as the active 20-nm thick layer into an OLED having an ITO electrode with a sheet resistance of 40 il cm-2, TPD as hole transporting layer with a thickness of 40 nm, and bathocuproine (BCP) (40 nm) as the electron injection and transporting layer (see fig. 117). The electroluminescence spectrum is identical to the photoluminescence emission the luminescence intensity at 1.07 pm versus current density curve deviates from linearity from approximately 10 mA cm-2 on, due to triplet-triplet annihilation. Near-IR electroluminescent efficiency <2el has been determined by comparison with [Eu(dbm)3bath] for which the total photoluminescence quantum yield in dmso-tig at a concentration of 1 mM is Dpi, = 6% upon ligand excitation, while its external electroluminescence efficiency is 0.14% (3.2 cdm-2 at 1 mAcm-2) ... 

FIGURE 4 Overpotential versus current density when the Tafel slope is 100 mV/decade. Low values of exchange-current density cause significant increases in overpotential at a specified current density. 

Fig. 34 a External quantum and power efficiencies versus current, b External quantum efficiency as a function of the doping concentration... 

Figure 1 Voltage versus current characteristics of gas discharges. (From Ref. 26.)...

CLs), resulting in a drastic drop in cell performance [17], Figure 3.13 also shows the difference between the theoretical cell potential (1.23 V) and the thermoneutral voltage (1.4 V), which represents the energy loss under reversible conditions (the reversible loss) [18], Very often, polarization curves are converted to power density versus current density plots by multiplying the cell voltage by the current density at each point of the curve. 

As a current (7) is swept between the two Pt gauze probes, the potential difference between the two sides of the membrane is measured as a function of current density. The plots of the potential difference (AEref) between the two SCEs versus current obey Ohm s law, and the slope of the plot gives the cell resistance (Rceii) according to Equation 5.10 ... 

Figure 6.161 Ignition probability versus current (according to [51]). Methane-air mixture, inductive circuits with ...

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