Triode cathode

Developments such as that of the vacuum triode, cathode ray tube and, later, the transistor and the solid-state integrated-circuit device, had an enormous influence on the design and construction of instruments. Electronic systems can respond with lightning speed to an almost-zero signal. The glass ion-sensitive electrode was discovered in the early 1900 s, but its appearance in the pH meter had to wait for developments in electronics. 

Triode sputteringxxsQS an additional cathode to sustain the plasma but is more complicated and may cause contamination of the deposit. 

Fig. 31 Proposed unimolecular amplifier DiD2A, in a circuit analogous to a grounded-emitter junction transistor, grounded-source FET, or grounded-cathode triode circuit. The arrows show the direction of preferred electron flow. The two Au and one A1 electrode tips must be about 3 nm apart...

The field emission display held a particular fascination for this field, because of its potentially large market [36,44-49]. Field emission displays (FEDs) are flat panel displays, which are a flat panel equivalent of the cathode ray tube (CRT), but in which each pixel is addressed by its own electron beam from a field emitter, rather than having a beam scanned across it as in the CRT (Fig. 13.8) [44]. The emitters can be diode or triode type. The triode type is the most elegant, the diode type is lower cost. 

Sputter-ion pumps of the triode type excel in contrast to the diode-type pumps in high-noble gas stability. Argon is pumped stably even at an inlet pressure of 1 10 mbar. The pumps can be started w/ithout difficulties at pressures higher than 1 10 mbar and can operate continuously at an air inlet producing a constant air pressure of 5 10 mbar. A new kind of design for the electrodes extends the service life of the cathodes by 50 %. 

Early hot cathode ionisation gauges were concentric triode gauges in which a central cathode was surrounded by a coaxial cylindrical ion collector. Because of the high X-ray limit, such gauges could only read down to 10 7mbar. From Equation (5.16), it can be seen that the situation could be improved by lowering /r. 

Abstract. This work is devoted to development of the effective electron gun for the triode light sources. The electron gun is based on field emission cathode made of a bundle of PAN carbon fibers encapsulated into a glass capillary. The complex of researches on optimization of electron-optical system has been carried out. 

The electron-optical system of the cathodoluminescent lamp consists of electron gun and luminescent screen, which is covered by phosphor. It represents the triode construction. The base of this triode is the cathode-modulator unit (CMU) that consists of field emission cathode and extraction electrode (modulator). 

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. 

Plot of plate current It, versus plate voltage Et, for various fixed values of the grid voltage Ec in a vacuum tube triode (common-cathode or grounded-cathode circuit). The grid is back-biased, the plate is forward-biased. Note that the curves are essentially the same, but are displaced along the plate voltage axis and resemble those of Fig. 9.8. In actual triodes the amplification factor varies and is not just simply the n — 5 used here. Adapted from Terman [5]. 

Characteristics of a typical common-cathode or grounded-cathode vacuum tube triode (curves of plate current /b versus plate voltage Eb, for different values of grid voltage Eg — Ec). The horizontal line connects points of constant plate current lb, and the vertical arrows show how Eq. (9.3.7) is applied to obtain the transconductance. Note that changing Eg only displaces the IV curve but, to first approximation, does not distort it. Adapted from Mandl [6]. 

Common-base, common-emitter, and common-collector circuits for a bipolar npn transistor (A, B, C, respectively), and the equivalent grounded-grid, grounded-cathode, and grounded-plate circuits for vacuum-tube triodes (A corresponds to A, B to B, and C to C). Adapted from Terman [5]. 

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-... 

It was established, that possibility of the control appears due to essential differences in conductivity of polymer layers. As in a vacuum triode, the conducting layer corresponds to an electronic cloud between grid and cathode. 

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