Shunt, resistive

Abzweigung,/. branching, branch, (Elec.) shunt. Abzweig(ungs)widersCand, m. (Elec.) shunt resistance. 

The losses, and hence the effective resistance, are also increased by passing the line in close proximity to a nonmsulatmg surface—for example, passing the line over seawater. The metal from which the conductor is made is also vei y important—for example, copper has a lower resistance, for the same geometry, than aluminum does. Also related to the losses of the transmission Hue is the shunt resistance. Under most circumstances, these losses are negligible because the conductors are so well insulated however, the losses become much more significant as the insulators supporting the transmission line become contaminated, or as atmospheric and other conditions result in corona on the line. 

When the intensity of a hollow cathode lamp increases because of a reduction in the shunt resistance, the profile of the emission line changes. As the central part of the cathode becomes very hot, the line is broadened for several reasons. However, vaporised atoms emitted by the cathode will reabsorb in a colder part of the lamp in the form of a very fine line. The net result is that the emission curve dips in the middle because of self-absorption. This observation is the basis of the pulsed lamp technique for correction of background absorption (Fig. 14.15). 

An alternative example is formed by the current fluctuations in a circuit consisting of a shunted resistance at constant temperature (fig. 7). 

The furnace is a Marshall high-temperature testing furnacet (d), with nine zones. Shunt resistances are placed selectively across the winding of the furnace to establish a thermal gradient across the 4-in. length of the boat, with the V-shaped end of the boat at the cool end of the gradient. A Pt—Pt— 10%Rh thermocouple is used... 

A process for the production of photodiodes by a planar technique is presented in US-A-3988774. A thin transition layer is formed between the substrate and a dielectric masking layer necessary for local diffusion to increase the shunt resistance of the photodiodes. The... 

For practical solar cells, the ideal equivalent circuit will be modified to include the series resistance from Ohmic loss in the two electrodes and the shunt resistance from leakage currents (Fig. 5.36a). The diode current for a realistic setup is then given by... 

The value of J in the exponent is different in the dark and in the illuminated situations. This invalidates the superposition principle. It can be easily demonstrated that shunt resistance will also invalidate the superposition principle. Under high intensity of illumination material parameters can change and also due to the different mobilities of electrons and... 

Here Jo is the dark saturation current density, Rs is the series resistance, A is the area and Rp is the shunt resistance. When a voltage V exists on the junction, the output current of the illuminated solar cell has two components, (1) the junction current density 7j (illumination) due to injection of carriers and (2) the short circuit current density Jsc due to light generated carriers. Therefore the output current density J v of the illuminated solar cell is given by,... 

Fill factor for DSC are hmited in general by series resistance losses, light-intensity dependent recombination, nonideal dark diode currents and, in some cases, shunt resistance losses. 

The measuring circuit is shown in Figure 2. A condenser, Cp, is inserted to remove influences resulting from the impedance of the electric power source. E is a shunt resistance used to measure the current wave form. The voltage wave form was measured by a cathode-ray potential divider. 

A second important factor in polymer polymer blend device design is the degree of vertical segregation of donor and acceptor polymers. This can be controlled by choice of solvent and processing (Arias et al, 2002), by thermal post-treatments (Veenstra et al, 2004) or by solution casting of consecutive layers. Vertical segregation can greatly improve the device shunt resistance. Currently, the best efficiencies for polymer-polymer solar cells is 1.5% for a blend of a PPV polymer with a red... 

I-V curves should be measured in the dark, before and after illumination, both to determine whether any device has developed microscopic shorts (during either device fabrication or testing) resulting in a low shunt resistance and to determine whether the test cell pins are properly contacting the relevant contacts on the device. Poor contact by these pins would result in a large series resistance and mask the behavior of the device under study. 

Figure I. (a) Experimental arrangement for the measurement of freezing potentials (10 K, resistor not in circuit) and currents (10 K. resistor shunting the phases), V = electrometer C = recorder, (b) Electric analog of the system in the shunt case, Rb = interface barrier resistance = external shunt resistance Rj = ice resistance Ri = solution resistance Rm = ice metal interface resistance c = interface charge separation...

When a shunt is used, two factors are important for the interpretation of results (a) The external shunt resistance carries only a fraction of the total neutralizing current, depending on freezing rate and ice length, (b) For an ice of a given composition, the ice/metal contact resistance depends on the material of the base, the nature of the surface. 

The eflFect of the shunt in Group I solutions may be interpreted in terms of an interface resistance which is virtually in parallel with the shunt resistance under the conditions specified above. Typically, the interface resistance is of the order of 10 to 10 ohms per cm- of interface (66,67). 

In the preceding section it was shown that differential ion transfer takes place at the phase boundary. This process can be modified by using a shunt resistance or by changing the solution pH or by altering the freezing rate. Differential ion transfer is a second-order phenomenon superimposed on the rejection, from the sohd, of the major portion of all the impurities, anions and cations alike. Thus, the solute becomes distributed unequally between the phases. The parameter governing the distribution is the solute partition coeflBcient, interface distribution co-eflScient, or simply distribution coeflBcient, defined as... 

The tight junction has also been implicated in the regulation of the transepithelial salt flux across proximal tubule. Measurements in Necturus proximal tubule have shown that when the animal is in a volume expanded state there can be a 3-fold decline in epithelial resistance due essentially to a change in the paracellular shunt resistance [61], In the volume expanded state then, although active transport of salt into the lateral interspace is little changed from the control conditions, enhanced backflux of salt across the tight junction into the lumen results in substantially diminished transepithelial salt flux [61-63]. These increases in junctional permeability are likely mediated by increases in peritubular (serosal) and hence, lateral interspace pressure [64,65]. 

Photovoltaic performance has been tested for the two polymers with a layered structure of glass/ITO/PEDOT PSS/polymer PCBM blend/LiF/Al. The PCE for POT-co-DOT is quite low, due to high dark current or low shunt resistance and low Vqc- Raising HOMO closer to LUMO of PCBM diminishes the values of Vqc- However, solar cells made from PF-co-DTB exhibits higher PCE with a high value of Vqc up to 0.76 V. The best obtained performance is from the blend with the wt. ratio of PE-co-DTB to PCBM being 1 4. The /sc is 4.31 mA/cm, V oc is 0.76 V, FF is 48.6%, and PCE is 1.6%. Annealing at 110°C increased the Vqc from 0.76 to 0.79 V. However, the /sc was decreased with no enhancement on the overall PCE. 

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