Transfer curves

Figure 10-54. Shell-side heat transfer curve for segmental baffles. (Used by permission Engineering Data Book Section II, 1959. Wolverine Tube, Inc.)...

Figure 10-156. Heat-transfer curve for annuli with longitudinal fins. (Adapted from DeLorenzo, B., and Anderson, E. D. Trans ASME, V. 67, No. 697, 1945. The American Society of Mechnical Engineers) (Used by permission Kern, D. Q., and Kraus, A. D. Extended Surface Heat Transfer, p. 464, 1972. McGraw-Hill, Inc. All rights reserved.)...

FIGURE 3-9 Square-wave voltammograms for reversible electron transfer. Curve A forward current. Curve B reverse current. Curve C net current. (Reproduced with permission from reference 9.)... 

Fig. 23. Schematic representation of quenehing by eleetron transfer. Curves a, b and c are levels of the pair Level d is a charge-transfer state...

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.

One of the more useful functions of the DC Sweep is to plot transfer curves. A transfer curve usually plots an input versus an output. A DC transfer curve plots an input versus an output, assuming all capacitors are open circuits and all inductors are short circuits. In a DC Sweep, all capacitors are replaced by open circuits and all inductors are replaced by short circuits. Thus the DC Sweep is ideal for DC transfer curves. The Transient Analysis can also be used for DC transfer curves, but you must run the analysis with low-frequency waveforms to eliminate the effects of capacitance and inductance. Usually a DC Sweep works better for a transfer curve. The one place where a transient analysis works better is plotting a hysteresis curve for a Schmitt Trigger. For a Schmitt Trigger, the input must go from positive to negative, and then from negative to positive to trace out the entire hysteresis loop. This is not possible with a DC Sweep. 

The screen capture above is the transfer curve for this circuit. 

EXERCISE 1-5 Find the transfer curve of the circuit below ... 

In the previous section, the question may arise as to how the Zener breakdown voltage affects the transfer curve. We will assume that you have followed the procedure of the previous section and have already set up the DC Sweep. 

EXEHCI5E 1-B For the circuit below, find the nested family of transfer curves if the breakdown voltage of the Zener is swept from 1 V to 6 V. 

We would like to plot the transfer curve Vo versus Vln for the NMOS inverter below ... 

The dialog box is set to sweep I/In from 0 volts to 5 volts in 0.001 volt steps (lm = 0.001). A linear sweep means that points will be equally spaced. Click the OK button to accept the settings. Run PSpice (select PSpice and then Run or press the F11 key). When the simulation is complete add the trace V(Vo) (select Trace and then Add Trace). The transfer curve is ... 

The name of the function is Voh. It has 2 input arguments (1,2). The first input will be the derivative of the trace, and the second input will be the trace itself. To use this function we would type Voh(d(V(Vo)), V(Vo)), where d(V(Vo)) is the derivative of the output trace and V(Vo) is the output trace. 1 search forward level means search the first input forward and find a level. The level we are looking for is -1. When the point is found, the text 1 designates its coordinates as xl and yl. Since the first input is the derivative of the trace, 11 search forward level (-1) 11 finds where the slope of the trace is -1. 2 search forward xvalue(xl) 2 searches the second input forward and finds the point when the x-coordinate is equal to x1. This point is where the slope of the transfer curve is -1. 12 marks the coordinates of this point as x2 and y2. The function returns the y-coordinate of this point Voh(1,2)=y2, which is equal to V0h-A second function is ... 

This function is used to find V0l and is similar to the Voh function. Note that Vol is also defined where the slope of the transfer curve is -1. To distinguish V0h and V0l. this function finds the point starting from the end of the trace and searching backwards. There are two points on the trace where the slope is -1. This function finds the point closest to the end of the trace. 

The goal functions are used in Probe. Follow the procedure of Section 4.D.3. When you obtain the Probe plot of the transfer curve V(Vo) versus V Vin below, continue with this section ... 

A question we would like to ask is, how does the transfer curve of the circuit from the previous section change as we change the driver MOSFET width-to-length ratio We would like a family of curves that show the effect of changing the driver width. Families of transfer curves can be generated using the Parametric Sweep in conjunction with the DC Sweep or by using the Secondary Sweep. The Secondary Sweep was demonstrated in Section 4.D.2, so we will demonstrate the Parametric Sweep here. 

EXEHCISE 1-3 In EXERCI5E 1-7 we looked at the operation of a CMOS inverter. We will now investigate how the (W/L) ratio of the PMOS transistor affects the transfer curve of the inverter. Let the (W/L) ratio of the PMOS transistor have values 1, 3, 6,9, 12, and 15. 

When you have a clipping circuit, as in the last example, a transfer curve may be desired. This can easily be done by changing the x-axis. A transfer curve usually plots VQ versus Vjn, so we need to change the x-axis from Time to VQ/IN). We must first delete the trace VflfINl from the plot above. Click the LEFT mouse button on the text V/VIN). The text will appear in red, indicating that it has been selected. Once the trace is selected, press the DELETE key to delete the trace. You can delete the other text items and lines on the screen using the same method. Click the LEFT mouse button on an item to select it and then press the DELETE key to delete it. You should have a screen with a single trace ... 

EXERCISE B-7 Find the output voltage waveform and the transfer curve for the circuit below. Let the input be a 15 volt triangle wave. Use the source Vtri to create a 1 Hz triangle wave. 

Curve b in Figure 1 shows the uptake curve for the same kg as in curve a but with only the external film resistance controlling the heat transfer. Curve c shows the corresponding isothermal uptake. These curves clearly... 

Figure 3 Literature discrepancies in drag coefficient, in mass transfer for CFB due to meso-scale structures and in char reaction rate coefficient. For the drag coefficients, curves are adapted from Wang et al. (2010) for the mass transfer, curves are adapted from Dong et al. (2008a) for the coal reaction, different symbols refer to different coal data.

Fig. 4.7. I-V characteristics of a typical PQT-12 TFT device with 90 pm channel length and 5000 pm channel width (a) output curves at different gate voltages (b) two transfer curves in saturated regime scanned from positive to...

Fig. 4.16. FET characteristics of a typical OTFT prepared with vacuum-deposited 5c (substrate at 70 °C channel length = 90 pm. channel width = 5000 pm) (A) output curves at different gate potentials (B) transfer curve...

HT-P3HTas channel semiconductor spin coated from 0.7% w/w solution in chlorobenzene at ambient. Transfer curves were obtained in the dark (red line) and then measured under white light (blue line) [57]. 

Fig. 5.1. Example of successive transfer curves obtained if bias stress is due to charge trapping in immobile states (a) and if bias stress is due to the formation of shallow donor-like states...

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