The triode age comprises the period
1913/35 when many innovations were introduced to the DeForest
device. These included high efficient cahodes, suitable
materials for the plates and grids, new type of glass for bulb
construction and advance technics in bulb evacuation.
In 1926, B.Tellegen, working at Philips laboratory invented
the pentode. Basically, the inner elements of this valve
consist of an additon grid mounted between the screen grid and
the anode. This third grid was later denoted the suppresor.
During the thirties other families of valves appeared in the
market: the output tetrodes and the beam-power valves, the catode
ray tubes, the tuning valve and finally the metallic and miniature
valves.(vide índice para informações complementares)
(quando colocar o mouse sobre a imagem,
ela será aumentada) |
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Dr. Lee de Forest and his invention
the thermionic valve, the spherical Audion which was the fundamental
of Electronics. The photograph was published in the American
magazine "Radio News" in May 1930. |
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Illustration of the first types
of triodes commercialized in U.S.A., circa the Twenties,
the left for the right: triode of DeForest type DV5
triode type WE 205D manufactured by the W. Electric
and a Socket for setting of the valve. |
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American and european valves |
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AMERICAN
AND EUROPEAN VALVES |
LEGEND |
ORIGIN |
TYPE |
MANUFACTURER |
DATE |
1 |
USA |
DV-3 |
DEFOREST
|
1923 |
2 |
USA |
101D |
W.ELECTRIC |
1924 |
3 |
USA |
24-A |
RCA |
1929 |
4 |
FRANCE |
E |
SFR |
1922 |
5 |
ENGLAND |
AC2/HL |
MAZDA
VALVE |
1928 |
6 |
HOLLAND |
C-509 |
PHILIPS |
1925 |
7 |
HOLLAND |
KK2 |
PHILIPS |
1933 |
8 |
USA |
UX
280 |
RCA |
1927 |
9 |
USA |
UX-201-A |
RCA |
1921 |
|
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