Output current-voltage characteristics

Potentiostatic limitations. Equation 5.2.11 predicts very high currents at short times, but the actual maximum current may depend on the current and voltage output characteristics of the potentiostat (Chapter 15). 

B.2.2 Voltage-mode Controlled Flyback Converter and Current-mode Controlled Forward-mode Converter Control-to-Output Characteristics... 

A comparison of typical properties of cathodic protection materials is given in Table 10.23, but is by no means comprehensive. It is obvious that the modification of an alloy, environment or other important factors will be reflected in the life and output characteristics. In some cases the maximum voltages and current densities recommended can be vastly exceeded. In others, particularly where abnormal levels of environmental dissolved solids are met, factors of safety should be applied to modify the proposed figures. Acceptance of a much reduced or uncertain life, weighed against a possible economy, may also influence the chosen working limits. For example, the life of ferrous alloy anodes may, in practice, be only two-thirds of that expected because of preferential attack eventually leading to disconnection of all or part of the anode from the source of e.m.f. 

To make the entire eleetronic response linear with respect to tunneling gap s, a logarithmic amplifier is attached at the output of the current amplifier. A logarithmic amplifier can be made from a feedback amplifier, by replacing the feedback resistor with a diode, as shown in Fig. 11.4. The current-voltage characteristics of a good-quality, forward-biased silicon diode follow an exponential law over more than five orders of magnitude ... 

Fig. 11.4. Logarithmic amplifier, (a) Schematic of a logarithmic amplifier. A diode is used as the feedback element in a current amplifier. The current-voltage characteristics are exponential. The output voltage is then proportional to the logarithm of the input current, (b) The transfer curve of a typical logarithmic amplifier, AD757N from Analog Devices. The reference current is internally set to be 10 p,A. It is accurate up to six decades.

Fig. 2.19. (a) Scheme of a transparent field effect transistor based on ZnO [191]. The gate electrode consists of tin-doped indium oxide (ITO) and the gate dielectric is a multilayer of AECE/TiCE (ATO). (b) Output characteristics (drain-source current as a function of the drain-source voltage) for different gate voltages. The saturation current is about 530 rA at a gate bias of 40 V. From this output characteristics a threshold voltage of 19 V and a field-effect mobility of 27 cm2 V-1 s-1 were calculated [192]... 

Figure 10 illustrates the short-term dc stability of the devices (Mackenzie et al, 1983). The output characteristics of one FET are shown for 10 successive scanning cycles of VG from —10 V to +45 V and back. The gate voltage was scanned in both directions at a rate of about 0.5 V sec-1. The traces show remarkably little drift or hysteresis in fact, the maximum variation in VG is approximately 0.4 V for a given value of source-drain current. 

Figure 6.226 Example of a limiting characteristic diagram according to PTB-Report PTB-ThEx-10. The output current/voltage diagram is indicated ( output characteristic ).

Figure 6. Typical ZnO-TFT characteristics with the channel layer deposited at room temperature by rf magnetron sputtering, for a TFT with a width-to-length ratio of 1.4. (a) Transfer characteristics for Vds = 20 V. The on/off ratio is 2x10. The ZnO-TFT operates in the enhancement mode with a threshold voltage of 21 V and a saturation mobility of 20 cmVVs. (b) Output characteristics for a ZnO-TFT. The saturation was about 230 pA under a gate bias of 40 V. The ZnO-TFT exhibits hard saturation, evidenced by the flatness of slope of each Ids curve, for large Vds- The dashed line represents the saturation drain current that follows an exponential dependence on the voltage.

The performance of PEMFC is often presented by the polarization curve that shows the voltage output as a function of current density. Fig. 8 shows a typical polarization curve of PEMFC. As the PEMFC processes charge-transfer reactions and the diffusion of the reactants to and products from the electrochemical interface, the transport and kinetics within the cell determine the polarization characteristics of PEMFC. In the practical PEMFC, the terminal cell potential V... 

Figure 8 shows power output characteristics of FGM thermoelectric sample shown in Figure 7. Voltage-Current plot and Power-Current plot show the difference in the direction of temperature gradient applied to the sample. Output power with forward temperature gradient is 6% larger than that with reversed temperature gradient. The most likely explanation of this asymmetry can be found in a graded structure of the sample. But there is room for argument on this result because there seems a problem on reproducibility of both the material properties and the soldering technique. In this study the expected enhancement on conversion efficiency is rather small, it seems necessary to solve the problem mentioned above.

When Pq and the interelectrode gap (d) have values greater than a specified value (Pq, d>20 mil Torr), the cesium ionizes and forms a plasma, referred to as the ignited mode. In this ignited mode, an output current density more than ten times that for the unignited mode is obtained. The output current-voltage characteristics obtained at Tg = 1800 K, 7 = 1000 K and Tg = 497 561 K are shown in Figure 7. 

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