John Mauchly

john-mauchlyJohn Mauchly grew up in Chevy Chase, Maryland. In 1927 he got a scholarship to the Johns Hopkins University, where he studied engineering but soon switched to physics, earning his first degree. In 1932 he earned a doctorate and taught physics at various colleges. Mauchly, who had been a physics professor at Ursinus College near Philadelphia before beginning work on ENIAC, often zipped around his classroom on a homemade, jet-propelled skateboard in order to demonstrate Newton’s laws of motion. By 1940 his interests were drawn toward building computers, and in 1941 he attended an electronics course taught by John Eckert at the Moore School of Electrical Engineering. Eckert shared his passion for computers, and they became close friends.

After a widely accepted report Mauchly wrote on computing, he and Eckert teamed together to build the ENIAC. He would later form the Eckert-Mauchly Corporation with Eckert and they built some of the most famous of the early computing machines.

After leaving Eckert-Mauchly in 1950, he formed Mauchly Associates and served as president from 1959 to 1965. He was awarded the Harry M. Goode Memorial Award in 1966. He received numerous other accolades and awards and ran two companies until his death in 1980.

John Eckert

john-eckertJ Presper Eckert Jr. attended the William Penn Carter School in Germanstown. In 1937, after graduating from school, he entered the Moore School of Electrical Engineering at the University of Pennsylvania from where he graduated in 1941. After graduation he was offered a teaching job at Moore, where he met John Mauchly. Mauchly had many ideas about the development of computers, and Eckert quickly became interested.

Later the two would collaborate on the ENIAC computer, one of the first computers of it’s kind in 1946. After it’s success, both left Moore and formed the Electric Control Company, and created the BINAC. Electric Control Company became Eckert-Mauchly in 1950 and continued to build some of the famous early computers. Eckert held patents on 85 inventions and numerous awards before his death in 1995.

Eckert-Mauchly Corporation

Eckert-Mauchly Corporation was formed by the scientists John Eckert and John Mauchly in the early 40s, designing and building some of the first famous computers in existence.

The company was incorporated December 22nd, 1947, originally called Electronic Control Corp. before being renamed. Although the two men built the ENIAC before forming the company, the first official Eckert Mauchly computer was the BINAC. The company was acquired by Remington Rand on February 15th, 1950. The first UNIVAC was not delivered until March 1951, over a year after EMCC was acquired by Remington Rand


binacThe BINAC was a bit serial binary computer designed by Eckert-Mauchly. It had a 512-word acoustic mercury delay line memory divided into 16 channels each holding 32 words of 31 bits with an additional 11-bit space between words to allow for circuit delays in switching. The clock rate was 4.25mh which yielded a word time of about 10 microseconds. The actual instruction execution rate was dominated by the access time for instructions and data and would have averaged about 3000-4000 instructions per second, unless minimum latency programming was employed. Each BINAC word held two instructions. Each instruction had a five bit operation code and a three octal digit address. All operands were 31-bit words. Arithmetic was two’s complement and there were single-bit arithmetic right and left shift instructions as well as addition, subtraction, multiplication and division. There were no logical instructions and no subroutine calls. Jump on negative was the only conditional instruction. The BINAC was the first dual processor computer, and was built for the U.S. Navy.

Vacuum Tubes

vacuumBack in 1904, British scientist John Ambrose Fleming first showed his device to convert an alternating current signal into direct current. The “Fleming diode” was based on an effect that Thomas Edison had first discovered in 1880, and had not put to useful work at the time. This diode essentially consisted of an incandescent light bulb with an extra electrode inside. When the bulb’s filament is heated white-hot, electrons are boiled off its surface and into the vacuum inside the bulb. If the extra electrode (also called an “plate” or “anode”) is made more positive than the hot filament, a direct current flows through the vacuum. And since the extra electrode is cold and the filament is hot, this current can only flow from the filament to the electrode, not the other way. So, AC signals can be converted into DC. Fleming’s diode was first used as a sensitive detector of the weak signals produced by the new wireless telegraph. Later (and to this day), the diode vacuum tube was used to convert AC into DC in power supplies for electronic equipment.


semiconductorPioneered with the advent of the first transistor using semiconductor materials at Bell Labs by John Bardeen and Walter Brattain, semiconductors have had a monumental impact on our society. You find them at the heart of microprocessor chips as well as transistors. Anything that’s computerized or uses radio waves depends on semiconductors. Today, most semiconductor chips and transistors are created with silicon. You may have heard expressions like “Silicon Valley” and the “silicon economy,” and that’s why — silicon is the heart of any electronic device.

Point Contact Resistor

pointThe first transistor was about half an inch high. That’s mammoth by today’s standards, when 7 million transistors can fit on a single computer chip. It was nevertheless an amazing piece of technology. It was built by Walter Brattain.

Before Brattain started, John Bardeen told him that they would need two metal contacts within .002 inches of each other — about the thickness of a sheet of paper. But the finest wires then were almost three times that width and couldn’t provide the kind of precision they needed. Instead of bothering with tiny wires, Brattain attached a single strip of gold foil over the point of a plastic triangle. With a razor blade, he sliced through the gold right at the tip of the triangle. Voila: two gold contacts just a hair-width apart.

The whole triangle was then held over a crystal of germanium on a spring, so that the contacts lightly touched the surface. The germanium itself sat on a metal plate attached to a voltage source. This contraption was the very first semiconductor amplifier, because when a bit of current came through one of the gold contacts, another even stronger current came out the other contact.

Here’s why it worked: Germanium is a semiconductor and, if properly treated, can either let lots of current through or let none through. This germanium had an excess of electrons, but when an electric signal traveled in through the gold foil, it injected holes (the opposite of electrons) into the surface. This created a thin layer along the top of the germanium with too few electrons.

This device was made using paper clips and razor blades, and was first used in an audio amplifier to present to Bell executives.