Integrated circuit , instrumental

A simple biopotential amplifier design based on an integrated-circuit instrumentation... 

Instruments based on the contact principle can further be divided into two classes mechanical thermometers and electrical thermometers. Mechanical thermometers are based on the thermal expansion of a gas, a liquid, or a solid material. They are simple, robust, and do not normally require power to operate. Electrical resistance thermometers utilize the connection between the electrical resistance and the sensor temperature. Thermocouples are based on the phenomenon, where a temperature-dependent voltage is created in a circuit of two different metals. Semiconductor thermometers have a diode or transistor probe, or a more advanced integrated circuit, where the voltage of the semiconductor junctions is temperature dependent. All electrical meters are easy to incorporate with modern data acquisition systems. A summary of contact thermometer properties is shown in Table 12.3. 

The analysis of tetramethylammonium hydroxide (TMAH) solutions manufactured by SACHEM Inc. of Cleburne, Texas, includes the determination of trace elements. These elements cause less-than-optimum performance of integrated circuit boards manufactured by SACHEM s customers that use these solutions in their processes. Alkali and alkaline earth metals (e.g., Li, Na, K, Mg, Ca, and Ba) can reduce the oxide breakdown voltage of the devices. In addition, transition and heavy metal elements (e.g., Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, Au, and Pb) can produce higher dark current. Doping elements (e.g., B, Al, Si, P, As, and Sn) can alter the operating characteristics of the devices. In SACHEM s quality control laboratory, ICP coupled to mass spectrometry is used to simultaneously analyze multiple trace elements in one sample in just 1 to 4 min. This ICP-MS instrument is a state-of-the-art instrument that can provide high throughput and low detection Emits at the parts per thousand level. Trace elemental determination at the parts per thousand level must be performed in a clean room so that trace elemental contamination from airborne particles can be minimized. 

In 1958, Jack Kilby (1923-2005), a researcher atTexas Instruments, invented a miniature electronic circuit known as an integrated circuit. Modern integrated circuits, which contain many electronic components etched on a thin wafer of silicon, have become a vital part of many devices, especially computers. Placing a large number of electronic components in such a small area has greatly reduced the size of electronic equipment. 

Texas Instruments researcher Jack Kilby (1923-2005) invents a tiny electronic circuit known as an integrated circuit, which rapidly becomes an important component of computers and other electronic devices. 

Three-Electrode Instruments for Polarography and Voltammetry In Fig. 5.45, if E connected to point a is a DC voltage source that generates a triangular voltage cycle, we can use the circuit of Fig. 5.45 for measurements in DC polarography as well as in linear sweep or cyclic voltammetry. An integrating circuit as in... 

The arrival of large-scale integrated circuits in the last 20 years has revolutionized chemical instrumentation just as it has kitchens, automobiles, and television sets. With respect to electrochemistry, the microprocessor has been incorporated in signal generation and data processing, while the basic instrumentation (e.g., potentiostat and current-to-voltage converter) remains as described in earlier sections of this chapter. Microprocessor instruments provide flexibility... 

The circuit may be easily constructed for a modest cost using inexpensive operational amplifiers and any of a number of integrated circuit oscillators that are commercially available. This basic piece of instrumentation is suitable for student laboratory experiments, conductometric monitoring of distilled water or... 

Semiconductors (Microchips)/Integrated Circuits/Components, Manufacturing Instrument Manufacturing, including Measurement, Control, Test Navigational Computers Electronics. Distribution Computer Telecommunications Equipment Distribution... 

In recent decades we have seen an explosion of various spectroscopic techniques for analyzing the elemental composition and chemical states of solid surfaces and films. This explosion has stemmed in part from the large number of surface- or interface-related problems seen in integrated-circuit performance, composite reliability, corrosion, nanostructured components, and so on. Instruments themselves can range from stand-alone units to attachments in national synchrotron facilities or multitechnique systems built around special fabrication sites. However, the basic principle of the technique, and therefore the basic concerns with sample preparation, stay the same. 

Over the last twenty five years, the instrumental techniques available to the analyst have become far more varied and of much better quality. This is to a large extent due to the advances which have been made in the field of electronics over the same period, with the development firstly of transistors, then simple integrated circuits, and more recently such complex and versatile devices as microprocessors. 

The basis of analogue instrumentation is the operational amplifier (OA), an integrated circuit that exists in various forms and with different characteristics according to the applications and requirements19. 

The description of the different types of protection in Chapter 6 indicates that there are two very different ways to solve this problem - if an electrical transmission is required at all. One way is to use intrinsically safe circuits, the other one applies industrial equipment as usual, additionally explosion protected by an enclosure as appropriate, e.g. flameproof housings for smallsized devices. In the history of process instrumentation, the appearance of semiconductors and integrated circuits has drastically reduced the power consumption of field devices. So, intrinsically safe circuits dominate this field today. 

The rapid development of solid-state electronic devices in the last two decades has had a profound effect on measurement capabilities in chemistry and other scientific fields. In this chapter we consider some of the physical aspects of the construction and function of electronic components such as resistors, capacitors, inductors, diodes, and transistors. The integration of these into small operational amplifier circuits is discussed, and various measurement applications are described. The use of these circuit elements in analog-to-digital converters and digital multimeters is emphasized in this chapter, but modern integrated circuits (ICs) have also greatly improved the capabilities of oscilloscopes, frequency counters, and other electronic instruments discussed in Chapter XIX. Finally, the use of potentiometers and bridge circuits, employed in a number of experiments in this text, is covered in the present chapter. 

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