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Current issue

ELEKTRO 7/2018 was released on June 27th 2018. Its digital version will be available on July 27th 2018.

Topic: Cables, conductors and cable engineering; Tools, equipment and accessories for work with cables

Main Article
Parametrization of circuit models of Li-accumulators for electromobility
Smart Cities (part 3 – volume 1)

SVĚTLO (Light) 4/2018 was released on July 30th 2018. Its digital version will be available on August 31th 2018.

Refreshing our memory
Eccentric luminaires of René Roubíček from the years1965 till 1977
Bases of photometry – 1st part
Great personage of Czech science of times after Battle at Bílá hora: doctor, naturalist, philosopher and physicist Jan Marek Marci from Kronland

Optical radiation effects and use
The light and circadian rhythms

Photovoltaics Discovered In 1875

06.01.2015 | |

 These days we are celebrating the UN’s 2015 Year of Light. Physicist John Perlin explains an excellent archive for any person wishing to keep abreast of today’s solar revolution.


The year: 1872. It was this discovery that stirred keen interest in two British scientists, William Grylls Adams and Richard Evans Day. Adams and Day had received from Smith the bars of selenium he had experimented with. Their goal? To delve deeper into the peculiar behavior Smith had discovered.


In one experiment, Adams and Day passed a battery-generated current through the bars. After detaching the battery from the selenium, they discovered to their astonishment that the induced current had reversed itself. To see if light would have the same effect as the battery had, the the two scientists placed candlelight close to the selenium. The flame forced the current to flow in the opposite direction as if it were a battery.


They therefore knew they had discovered something previously unknown to science – that a current could be started by the action of “light alone” in a solid-state material.The two scientists called the flow of electricity caused by light, “photoelectric.” Today, we say, “photovoltaic.” So began in 1875 the first stirrings of today’s solar revolution.

read more cleantechnica.com

Image credit John Perlin: Let It Shine

 

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