Heinrich Rudolf Hertz


"I do not think that the wireless waves I have discovered will have any practical application." (H.R.Hertz)


The German physicist Heinrich Rudolf Hertz was born on February 22, 1857, in Hamburg, as the son of a local lawyer. He showed an early aptitude for science, languages – he would even learn Arabic and Sanskrit – mathematics and mechanics, probably influenced by his parents having a family workshop at home where the young Heinrich enjoyed spending his time building instruments.

Hertz did his college studies in science and engineering at the University of Munich but later switched to the University of Berlin where he received his Ph.D. in Physics magna cum laude in 1880. He studied under the famous physicist Hermann von Helmholtz who encouraged him to attempt to win the University’s science prize. This would lead to some of Hertz’ most important discoveries.

In 1883 Hertz became a lecturer in theoretical physics at the University of Kriel and in 1885 he became a full professor at the University of Karlsruhe.



Wireless waves

In 1873 the British scientist James Clerk Maxwell (See Mexico stamp, RH side) had predicted, by mathematical equations, that producing electromagnetic waves in air was possible because electric oscillations would produce waves travelling through the air at the speed of light, but the experimental evidence for these electromagnetic waves was still lacking. It was Hertz who, in 1887, built an oscillator with polished brass knobs each connected to an induction coil. A few meters away he placed a looped wire to act as the receiver. When he switched on the oscillator and noticed the oscillating effect induced on the wired loop, he had managed the first transmission and reception of radio waves. He also noticed that the waves were reflected by electrical conductors, could pass through non-conducting elements and that they could be focussed by concave reflectors. His experiments enabled him to time the waves, thereby showing conclusive proof that the velocity of radio waves was equal to the velocity of light, something Maxwell had only theorized.

Hertz' students at Karlsruhe University, where he had set up the experiment in his physics classroom, wondered what use could be made of this phenomenon. Hertz, who saw no practical application of his accomplishment, replied “It’s of no use whatsoever.” He modestly underestimated his own achievement. Within a few years it would trigger inventions like the wireless telegraph and radio, soon to be followed by radar and television. Hertz had become, so to speak, the grandfather of our modern "bluetooth" technology. Hertz is also the cause of the British using the old-fashioned word “wireless” for a radio.

In 1888, Hertz published an article on his oscillator and how he managed to transmit and receive electromagnetic waves with it, in an electrical journal. This article was read by a young Marconi (he was only 14 years of age at that time) while enjoying his vacation in the Alps. Marconi surmised that the Hertz’ oscillator waves could also be used for signalling. He rushed home to try out this new idea. By adding an insulated aerial he managed to increase the transmission distance and a few years later (1898) he founded the Marconi's Wireless Telegraph Company in London.

Hertz would undoubtedly have made many more scientific discoveries but his life was cut short at the young age of 36. In 1892, he was diagnosed with a bone malignancy for which he underwent several operations. Following an infection, he died of blood poisoning on January 1, 1894, in Bonn, Germany.


Computer jargon: Hertz becomes Hz

Hertz has been honoured by having the unit of frequency named after him, the hertz – abbreviated as Hz. Although “frequency” refers to the number of times a repeated event occurs per unit of time (usually per second) it is mostly used for indicating radio and electrical frequencies. Within a computer environment the term is used to measure the clock speed of a computer processor.A computer’s clock speed is determined by a quartz crystal which oscillates at a certain frequency and is usually expressed in MHz (mega-hertz, million of cycles/second) or GHz (giga-hertz, billion of cycles/second).

When Ed Roberts (stamp on the left) introduced the first commercial PC, the Altair, in 1975, his computer had a clock speed of only 2 MHz. The first IBM PC (1981, stamp on the right) had a clock speed of 4.77 MHz. In 1995, this had gone up to 100 MHz, when Intel introduced the first Pentium chip. The Pentium-4 chip has a speed of 3 GHz (3,000,000,000 cycles/second). Currently (2007) PCs and laptops tend to have an effective speed of between 2 GHz and 8 GHz, quite an increase over the last thirty years. Actual frequency is usually around 2 GHz, but instead of increasing it, which would generate excessive heat, manufacturers nowadays place more than one processor “core” on a chip, effectively doubling or quadrupling the speed of the CPU.


How important is clock speed?

Most computer processors execute one or more basic instructions, like adding two numbers together, per clock cycle. Hence, it comes at no surprise that computer manufacturers often have used clock speed to advertise the superiority of their product to the digitally uninformed public. But there are many factors influencing the performance of a computer, with clock speed being only one of them. Its system architecture, operating system, the amount of memory, bus architecture, its instruction set and even its workload, all contribute towards a computer’s performance. Only a proper benchmark on a defined workload can determine the performance of a computer processor. Don’t get bamboozled by just the clock speed when you buy a new computer.



© Wobbe Vegter, 2007







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