4000 series

The 4000 series is a family of industry-standard integrated circuits (ICs) which implement a variety of logic functions using Complementary Metal–Oxide–Semiconductor (CMOS) technology, which were introduced in 1968 and are still in use today. Almost all IC manufacturers active during the era fabricated chips from this series. RCA sometimes advertised the line as COSMOS, standing for COmplementary Symmetry Metal-Oxide Semiconductor. The naming system followed the RCA convention of CA for analog, CD for digital, but did not relate to the Texas Instruments SN7400 series numbering scheme.

4000 series parts have the advantage of lower power consumption, wider range of supply voltages (3 V to 15 V), and simpler circuit design due to the vastly increased fanout. However their slower speed (initially about 1 MHz operation, compared with bipolar TTL's 10 MHz) limits their applications to static or low-speed designs. New fabrication technology has largely overcome the speed problems, while retaining backward compatibility with most circuit designs. Although all semiconductors can be damaged by electrostatic discharge, the high impedance of CMOS inputs makes them more susceptible than bipolar transistor-based TTL devices. Eventually, the advantages of CMOS (especially the later 74HC series) phased out the older TTL chips, but at the same time ever increasing LSI techniques phased out the modular chip approach to design. The 4000 series also contains many chips with a considerably higher level of integration than most basic logic chips, including fully integrated 7-segment display counters, walking ring counters, and full adders.

Chicago "L" rolling stock

The rolling stock of the Chicago "L" rapid transit system consists of railcars (permanently coupled into married pairs) dating from 1981 to 2015, delivered in two series: the 2600-series and 3200-series, also known as the High Performance Family, because of innovative design and technological features from previous equipment in Chicago transit beginning with the former 2000-series cars which operated between 1964 and 1993. The third fleet of cars in the rolling stock known as the 5000-series are the newest to the Chicago "L" featuring new technologies such as exterior and interior LED signs, security cameras, new seating configuration, AC motors and new door action.

All cars are 12 ft (3.66 m) tall (from top of rail) and 48 ft 3 in (14.71 m) long (over coupler pulling faces). They are 9 ft 4 in (2.84 m) wide at the window sills but only 8 ft 8 in (2.64 m) wide at the door sills. Currently, most railcars operating on the Chicago "L" are DC power only; the 5000-series features AC motors, but the traction power supply continues to use DC.

4000 series (disambiguation)

4000 series may refer to:

Integrated electronic circuits

Japanese train types

Korean train types