Encyclopedia of Electronic Components Volume 3

Abstract

This third and final volume of the Encyclopedia of Electronic Components is devoted entirely to sensors. Two factors have caused very significant changes in the field of sensors since the 1980s. First, features such as antilock braking, airbags, and emissions controls stimulated the development of low-priced sensors for automotive applications. Many of these sensors were fabricated in silicon as MEMS (microelectromechanical) devices. The second wave began in 2007 when MEMS sensors were installed in the iPhone. A modern phone may contain almost a dozen different types of sensors, and their size and price have been driven down to a point that would have been unimaginable 20 years previously. Many MEMS sensors are now as cheap as basic semiconductor components such as a voltage regulator or a logic chip, and they are easy to use in conjunction with microcontrollers. In this Encyclopedia, we have allocated significant space to this segment of the market, hoping that the specific products that we have chosen will remain popular and available for at least the next decade. In addition, we have devoted space to older components where durability has been proven. Purpose While much of the information in this volume can be found dispersed among datasheets, introductory texts, Internet sites, and technical briefings published by manufacturers, we believe there is a real need for a durable resource that assembles all the relevant data in one place, properly organized and verified, including details that may be hard to find elsewhere. This volume may also serve a useful purpose by attempting to categorize and classify components in a field that is remarkably chaotic. For example, is an object presence sensor different from a proximity sensor? Some manufacturers seem to think so; others disagree. Understanding the distinctions and the underlying principles can be important if you are trying to decide which sensor to use. Sensor terminology can also be confusing. To take another example, what is the difference between a reflective interrupter, a reflective object sensor, a reflective optical sensor, a reflective photointerrupter, and an opt-pass sensor? These terms are used in various datasheets to describe components that are all retroreflective sensors. Understanding the proliferating variety of terminology can be essential if you simply want to find something in a product index