Power electronics

Power electronics makes up a large part of engineering a nd has close connections with many areas of 
physics, chemistry, and mechanics. It establishes  a rapidly expanding field in electrical engineering 
and a scope of its technology covers a wide spectru m. Power applications with electronic converters 
do a lot of difficult work for us. Optimists envision power electronics doing more and more things for 
the population. Electronic appliances contribute to  a healthier and more comfortable live the world 

over. Thanks to advances in science and related t echnology, many people no longer have to spend 
much time working for the bare necessities of life. Whatever it is that we really want to do, power 
electronics helps us to do it better. 
Historical background. In terms of world history, power electronics is a young science. The earliest 
studied in the field of power electr onics date back to the end of the 19
th
 century. In 1882, French 
physicist J. Jasmin discovered a phenomenon of semic onductance and proposed this effect to be used 
for ac rectifying. In 1892, German researcher L. Ar ons invented the first mercury arc vacuum valve. 
P.C. Hewitt developed the first arc valve in 1901 in  USA and a year later, he patented the mercury 
rectifier. In 1906, J.A. Fleming invented the first vacuum diode, American electrician G.W. Pickard 
proposed the silicon valve, and L. Forest patented  the vacuum tube. The development of electronic 
amplifiers started with this invention and in 1907, a vacuum triode was built by L. Forest. Later, based 
on the same principles different kinds of electronic  devices were worked out. A key to the technology 
was the invention of the feedback amplifier by H.S. Black in 1927. In 1921, F.W. Meyer from 
Germany first formulated the main principles and trends of power electronics. 

In the first half of the 20
th
 century, electronic equipment was mainly based on vacuum tubes, such as 
gas-discharge valves, thyratrons, mercury arc rec tifiers, and ignitrons. Until the end of the 1920
th
, 
vacuum diodes (kenotrones) were the main electronic devices. In the 1930
th
, they were replaced by 
mercury equipment. The majority of valves were arranged as coaxial closed cylinders round the 
cathode. Valves that were more complex contained  several gridded electrodes between the cathode 
and anode. The vacuum tube had a set of disadvantages.  First, it had an internal power heater. Second, 
its life was limited by a few thousand hours before its filament burns out. Third, it was bulky. Fourth, 
it gave off heat that raised the internal temperat ure of the electronics equipment. Because of vacuum 
tube technology, the first electronic devices were very  expensive and dissipated a great deal of power. 

The first electronics revolution began in 1948 with the invention of the transistor by American 
scientists J. Bardeen, W.H. Brattain, and W.B. Shoc kley from “Bell Labs”. Later they were awarded a 
Nobel Prize for this invention. Most of today’s advanced electronic technologies are traceable to that 
invention. From 1952, “General Electric” manufactured the first germanium diodes. In 1954, G. Teal 
at “Texas Instruments” produced a silicon transist or, which gained wide commercial acceptance 
because of the increased temperature perf ormance and reliability. During the mid 1950
th
 through to the 
early 1960
th
, electronic circuit designs began to migrate from vacuum tubes to transistors, thereby 
opening up many new possibilities in research and development projects.