Triode anode

High-frequency power for industrial use is generated by a standard oscillator circuit operating under Class C conditions (that is, modified Colpitts, modified Hartley, tuned anode/tuned grid), using industrial triode valves, usually with ceramic envelopes and air- or water-cooled anodes. 

A) If Ec< 0 is applied in a triode, then the plate current 4 versus plate voltage Eb curve is shifted from Eq. (9.3.2), so that the plate current is reduced considerably (see Fig. 9.7). Indeed, at some sufficiently negative Ec, Ip becomes zero this occurs when the grid voltage E, is sufficiently negative to neutralize the positive cathode-to-anode field created by the positive plate voltage Eb. 

Vacuum fluorescent displays (VFDs) are strongly related to flat-panel CRTs. Electrons are ejected from a cathode source, traverse a vacuum and then strike a pattern of triodes with individual anodes covered in red, green and blue phosphorescent material. However, the operating voltages, e.g. 12 V, and power consumption are much lower than those found for CRTs and PDFs. 

The sensor consisted of a vacuum tube containing a filament, grid and anode, very similar in form to the thermionic triode valve. An adjustable leak was arranged to feed a portion of the column eluent into the gauge which was operated under reduced pressure. The sensor was fitted with its own pumping system and vacuum gauge and the usual necessary cold traps. Helium was used as a carrier gas and the grid collector-electrode was set at +18 V with respect to the cathode... 

An electron source. or electron gun traditionally the most frequent is the triode gun comprising a tungsten wire cathode heated to around 2 700 K. The electrons emitted by the cathode are accelerated by the electric field set up between this negatively polarised filament and the earthed anode. This gun can provide an electron beam of 30 keV with a current density per unit solid angle (also called bright-... 

A number of variations have been introduced to improve the efficiency of the deposition process. Instead of a dc potential, a radio-frequency voltage can be used to maintain the plasma ( rf-sputtering ). Deposition rates may be increased by adding a focusing system or magnetron. Another improvement makes use of a separate anode to produce the plasma and to preserve the quality of the target. This system is known as a triode. 

Example 1.6. In an electron tube, a triode, the anode current / is a function of the anode voltage Ua and the grid voltage Ug. The change of the anode current is... 

Figure 2 Structure of the polymer grid triode with the various layers. (1) and (5) are the cathode and anode (pixel) arrays, respectively. The other layers are continuous films common to all the PGTs within the array (2) and(4) are semiconducting layers, poly(2-methoxy-5-(2 -ethyl-hexyloxy)-1,4-phenylene vinylene), MEH-PPV, and (3) is the common grid network filled with semiconductor (3 ).

To build a full plastic retina, the polymer grid triode image enhancement array would be fabricated directly onto the output (back) side of a photodetector array (for example an infrared detector array) using each detector output pad as the anode or cathode of the PGT at that node. The semiconductor layers would be cast sequentially from solution and applied onto the detector array much like an antireflection coating. The final contrast enhanced output would be connected to a demultiplexer by bump-bonding that is by cold-welding indium bumps arrayed reciprocally on die PGT array output and on e demultiplexer input. 

The electron chamber has a demountable triode electron gun with a very compact metal-ceramic insulator profile that can support voltages up to 100 kV. Cathode replacement is a routine bench operation with adjustments for concentricity and axial spacing relative to the Wehnelt electrode for optimum AVcw The electron gun is mounted on a three-axis traverse for alignment with the first anode and for adjustment in the extraction gap to provide optimum AV a over the energy range 0 to 100 to keV. 

In order to compensate for this loss of brightness at low voltage, a new double-anode LaB gun has recently been developed, and is used at present on the ISI IC-130 SEM. This is illustrated schematically in Fig. 13. In the example shown, the gun is operated at IkV. The electron beam is first accelerated to 8kV by the first anode, to which a fixed 7kV potential is applied. A crossover is formed between the two anodes with a brightness equivalent to a triode gun operated at 8kV. The beam is then decelerated to IkV on passing through the grounded second anode, while... 

An electron gun is placed on top of this column. This gun usually consists of a thermionic cathode made of tungsten or LaBg in a triode configuration, i.e., an additional electrode (Wehnelt) between the filament and anode. The pressure in the specimen chamber is 10 -10 Pa. This pressure is much... 

The simplest and still the most widely used electron gun is the triode gun, consisting of a heated filament or cathode, an anode held at a high positive potential relative to the cathode, and, between the two, a control electrode known as the wehnelt. The latter is held at a small negative potential relative to the cathode and serves to define the area of the cathode from which electrons are emitted. The electrons converge to a waist, known as the crossover, which is frequently within the gun itself (Fig. 9). If jc is the current density at the center of this crossover and 0 s is the angular spread (defined in Fig. 9), then... 

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