Voltage applying

Figure C2.13.7. Change between polymerizing and etching conditions in a fluorocarbon plasma as detennined by tire fluorine-to-carbon ratio of chemically reactive species and tire bias voltage applied to tire substrate surface [36].

FIG. 22-36 Efficiency of an electrofilter as a function of gas flow rate at 5 different voltages. Experimental materials l- im aerosol of dioctyl phthalate glass-fiher filter. Symbols O, no voltage applied A, 2 kV , 3.5 kV , 5 kV , 7 kV. After Fielting et ah, Dielectrophoretic Filtration of Solid and Liquid Aerosol Particulates, Prepr. 75-32.2, 68th ann. meet., AirPollut. Conttol Assoc., Boston, June 1975.)... 

Locked-rotor (static) torque, starting, or breakaway The minimum torque that a motor will develop at rest for all angular positions of the rotor, with rated voltage applied at rated frequency. 

Breakdown torque For an alternating current motor, this is the maximum torque that it will develop with rated voltage applied at rated frequency, without an abrupt drop in speed. 

Secondary Voltage of Wound-Rotor Motors. The secondary voltage of wound-rotor motors is the open-circuit voltage at standstill, measured across the slip rings, with rated voltage applied on the primary winding. 

Pull-Out Torque. The pull-out torque of a synchronous motor is the maximum sustained torque that the motor will develop at synchronous speed with rated voltage applied at rated frequency and with normal excitation. 

In a brushless system an a.c. exciter with a rotating armature and stationary field system is provided. The voltage applied to the stationary field system is varied, thus changing the output of the rotating armature. This output is rectified via shaft-mounted diodes to produce a direct current (D.C.) supply that is connected to the main generator field. 

The invention of the germanium transistor in 1947 [I, 2] marked the birth of modem microelectronics, a revolution that has profoundly influenced our current way of life. This early device was actually a bipolar transistor, a structure that is mainly used nowadays in amplifiers. However, logical circuits, and particularly microprocessors, preferentially use field-effect transistors (FETs), the concept of which was first proposed by Lilicnficld in 1930 [3], but was not used as a practical application until 1960 [4]. In a FET, the current flowing between two electrodes is controlled by the voltage applied to a third electrode. This operating mode recalls that of the vacuum triode, which was the building block of earlier radio and TV sets, and of the first electronic computers. 

In a MESFET, a Schottky gate contact is used to modulate the source-drain current. As shown in Figure 14-6b, in an //-channel MESFET, two n+ source and drain regions are connected to an //-type channel. The width of the depletion layer, and hence that of the channel, is modulated by the voltage applied to the Schottky gate. In a normally off device (Fig. 14-9 a), the channel is totally depleted at zero gate bias, whereas it is only partially depleted in a normally on device (Fig. 14-9 b). 

The first realization of a conjugated polymer/fullerene diode [89] was achieved only recently after the detection of the ultrafasl phoioinduced electron transfer for an lTO/MEH-PPV/CW)/Au system. The device is shown in Figure 15-18. Figure 15-19 shows the current-voltage characteristics of such a bilayer in the dark at room temperature. The devices discussed in the following section typically had a thickness of 100 nm for the MEH-PPV as well as the fullerene layer. Positive bias is defined as positive voltage applied to the 1TO contact. The exponential current tum-on at 0.5 V in forward bias is clearly observable. The rectification ratio at 2 V is approximately l()4. 

Consider the apparatus shown in Figure 14-3. A glass tube is fitted with electrodes so that a potential difference of 10,000 volts can be applied across a space filled with a desired gas at various pressures. Suppose neon, for example, is placed in the tube. With the voltage applied, the gas will begin to conduct electricity when its pressure is reduced to about 0.01 atmosphere. The tube then glows with the familiar color of a neon sign. If a different gas is used, the color is different, but otherwise, the behavior is about the same. If the pressure is reduced still further to about 10 atmosphere, the glow from the gas... 

The simple electrical circuit shown in Fig. 16.15(h) is suitable for this procedure. The voltage applied to the titration cell is supplied by two 1.5 V dry cells and is controlled by the potential divider R (a 50-100 ohm variable resistance) it can be measured on the digital voltmeter V. The current flowing is read on the micro-ammeter M. 

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