7490 Decade Counter

A 7490 integrated circuit providing a decade counter. Counts from 0 to 9 then resets, in BCD. Combined with a 7447 and a seven-segment display it forms a complete counting display, which is one of the classic digital electronics teaching exercises. This is standard 74-series TTL logic, which runs specifically on 5 volts and is faster than 4000-series CMOS but draws considerably more current and will not tolerate other supply voltages. If your circuit runs at 3.3V or on batteries, ask us about the 74HC equivalent, which uses the same pinout and function but works from 2 to 6 volts at far lower current. Fast switching compared with 4000-series CMOS; Standard 14-pin DIP fits breadboards and sockets; Extensively documented in textbooks and coursework; Direct 5V logic compatibility with Arduino outputs