Models diodes

Figure 6. Configuration of the thermal diode model based on two coupled FK chains. 

In a recent paper (Li Wang Casati, 2004), a thermal diode model has been proposed in which, even though the underlying physical mechanism is similar to the one in Ref.(Terrano et al, 2002), there is a new crucial element which allows to improve the efficiency by more than two orders of magnitude. 

The diode model consists of two segments of nonlinear lattices coupled together by a harmonic spring with constant strength kint (see Fig. 6). Each segment is described by the (dimensionless) Hamiltonian ... 

The key point of our transistor model is the negative differential heat resistance as we observed in the diode model(Li Wang Casati, 2004). It provides the possibility that when Ta changes both Js and Jd change simultaneously in the same way. Therefore Js = Jd (or Js Jd) can be achieved for several different values of T0 or even in a wide region of T0 as shown in Figs.10 and 11. In this situation heat switch and heat modulator/amplifier are possible. In the ideal, limiting... 

Both turn-on and turnoff snubber circuits used the fast-recovery silicon diode (model number MUR 4100E). 

After we save the model, it is listed in the left window pane. This window pane lists all of the models contained in the library we are editing, in this case Section 3C.lib. Select File and then Exit to return to the schematic. Notice that the diode model name has changed from Dbreak to DX ... 

Most of the devices used by PSpice can include temperature effects in the model. Most of the semiconductor models provided by Oread include temperature dependence. By default, the passive devices such as resistors, capacitors, and inductors do not include temperature dependence. To make these items include temperature effects, you will need to create models that include temperature effects. The temperature dependence of resistors is discussed in Section 4.G.I. In this section, we will show only how the I-V characteristic of a 1N5401 diode is affected by temperature. The D1N5401 diode model already includes temperature effects so we will not need to modify the model. We will use the standard resistor, which does not include temperature effects. We will continue with the circuit of Section 4.B ... 

There are three ways to create new models in PSpice. One way is to modify an existing model and give it a new name. The second way is to get a breakout part and create a new model. The third way is to create a new model using Oread s Parts program. Since the Lite version of Parts creates only diode models, we will not discuss it here. The breakout parts are contained in the library called BREAKOUT. This library contains graphic symbols for all parts available in Capture. 

DbreakZ Zener diode model. The PSpice models used to create a diode and a Zener diode are the same. The only difference is in the graphic symbols of the parts. 

The diode model is used to create rectifier, signal, and Zener diodes. 

Examining the results of Fig. 6.38, it is noted that there was no state change when the input signal transitioned between 2 V and 5 V. Upon further examination, the culprit was determined to be the Micro-Cap zener diode model 1N4733. 

PSpice did not have a similar zener diode in its library, so a 1N4728 zener diode model was downloaded from an unnamed Web site. You could also use a voltage source set at 3.3 V in place of the zener. This would assume that the zener is used at its test current, IZT, which biases the PSpice results however, if asked to build this circuit by using only the models that were contained in PSpice, this would be a natural assumption to make. 

The amplitude of the SPICE model result has about a 1-V offset missing from the result. This is due to the forward drop of the zener diode, which is not typically modeled in zener diode models. It is not difficult to model this parameter, but since the purpose was to show the zero offset result, it is not important here. 

Examining Fig. 10.17, it is interesting to note the Micro-Cap and IsSpice results are very similar, the PSpice results are slightly higher, and the breadboard data falls in between the simulations. Suspecting the culprit to be the diode models, these were examined more closely. 

In Fig. 10.19, the traces, from top to bottom, are Ron Kielkowski s model, the Micro-Cap model, the IsSpice model, the measured data from a 1N4002 from the quadrupler circuit, and the PSpice model. The measured data is the dotted line. All of the diode data is similar. The differences from the breadboard diode, as explained above, are largely due to manufacturing tolerances, different manufacturers, and lot-to-lot variations. Ron Kielkowski s model was taken from the data for an actual 1N4002 diode as well. Figure 10.19 is a good example of how differences in models do not indicate their correctness. It is easy to construct a SPICE-compatible diode model that will exactly trace the curve of the breadboard 1N4002 however it would still be valid only for the exact breadboard modeled with that diode. 

The observed experimental result that Voc decreases linearly for bulk heterojunction solar cells allows us to conclude that, at least in the high temperature range (T > 200 K), these solar cells may be described by a diode model with Ip exp(E/kT). Here E is a parameter analogous to Eg for conventional semiconductors. For conjugated polymer/fullerene bulk heterojunction solar cells, E should correspond to the energy difference between the HOMO level of the donor and the LUMO level of the acceptor components of the active layer [as also suggested by the extrapolated value of V oc(0 K)]. 

Abstract. Copper phthalocyanine (CuPc)-fullerene (C60) photovoltaic cells are produced by organic vapour phase deposition reaching efficiencies of 3%. The electronic transport properties of the devices are investigated as a function of the CuPc C60 absorber blend layer composition and its preparation temperature. The analysis of the transport properties of the devices employs the one-diode model. It is shown that the dominant recombination process takes place at the donor-acceptor interfaces of the CuPc and C60 absorber domains. The activation energy of recombination is related to the effective band gap of the blend layer. 

Measurements of the J-V characteristics as a function of temperature (JV-T) and illumination were performed in an evacuated custom made N2-cooled cryostat. A set of neutral density filters (SCHOTT) served for adjusting the illumination, ranging from 5 x 10 4 mW/cm2 to 100 mW/cm2. The J-V curves were analysed by the one-diode model developed for inorganic thin film solar cells [5],... 

The ideal diode thermionic converter model corresponds to a thermionic converter in which the emitter and collector are spaced so closely that no collisional or space charge effects take place. To reduce the complexity of the equations, ion emission effects will also be neglected. Although these assumptions do not strictly correspond to any thermionic converter, they do approach those of a very closely spaced diode operating in the vacuum mode. The ideal diode model defines the performance limit imposed by essential electron emission and heat transfer and provides a basis for comparison with practical converters. 

Device Models of Bulk Heterojunction Solar Cells. 10-27 The Equivalent Circuit Model Extended One-Diode Model Electric Field-Dependent Dissociation of the Coulomb-Coupled E-H Pairs Numerical Solution to the Drift-Diffusion Equations... 

A simple replacement circuit based on one-diode model of a solar cell, shown in the inset of Figure 10.21, consists of a diode (represented by its quality factor n, and the reverse bias, dark saturation current jo), and a series resistor and a parallel resistor Rp that account for ohmic losses and shunt leakage through the diode, respectively. The photocurrent generation is represented by a current source jpi,. 

FIGURE 10.21 Current density-voltage curves of bulk heterojunction solar cells under 80 mW cm stimulated AM 1.5 illumination. The inset shows the replacement circuit of a one-diode model. 

Figure 11.4 shows the OLED model used in this Chapter. The model consists of a series resistance and a diode parallel with a capacitor. The capacitor models the total capacitance of the layers, the series resistance models the total resistance of the device and the diode models the rectifying nature of the OLED, the model is based on the... 

Fig. 2.9 Bond graph of the diode model capturing both modes...

In previous sections we have commented on the success of the fundamental diode model, based on electron density in the conduction band, and phenomenological... 

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