At a time when microprocessors containing millions of transistors, fiber optic networks, HDSL (high-bit-rate digital subscriber line) and ADSL (asymmetrical digital subscriber line) two new products in the field of telecommunication and fast data transfers and other advanced technologies of electronic circuits and systems are becoming commonplace, it may appear somewhat odd and anachronistic to write a book on resistive components and related products.

It is worth pointing out, however, that the physical relationship expressed by Ohm's law is still one of the most frequently used relationships in developing active and passive components. Without Ohm's law, and without resistors, there would be no possibility of measuring or recording a large number of phenomena and their changes.

The controls of a Boeing 737 or Airbus 320 are activated by the pilot by means of resistive movement sensors. Although the digital data on the tracks of a computer are read and written with inductive devices, magnetoresistive sensors can be used for the readout of data from the hard disks. Since two or three years ago, this technology is now widely used by the market. Old-fashioned wirewound resistors are still used in many electronic applications, especially power controls for fast railway trains, or shunts applications in power sensors.

At the same time, the constraints of miniaturization imposed by passive components have led manufacturers of resistive products to adopt methods of miniaturization and integration currently used in the production of printed circuits. A 16-bit R-2R network now requires a silicon area of only 1 to 2...