Not A Lightweight

Without the innovations of transistors and microprocessors, your laptop would be the size of a skyscraper and take a hydroelectric dam to power it. ENIAC, an early computer, designed by the U.S. Army to automate the process of making fast and accurate artillery calculations during World War II, filled a 30-by-50-foot room and weighed more than 27 tons. It used 174 kilowatts per second--enough to power a typical home for more than a week. ENIAC contained 17,468 fragile vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5 million hand-soldered joints. It could store twenty 10-digit numbers in its memory, and it cost roughly $450,000. A handheld calculator now offers more computing power than ENIAC. A modern laptop computer weighs around 5 lbs. with most of the weight coming from the rechargeable battery that powers the computer--an amazing feat of innovation and miniaturization.