Short history of the Philips electron tube (electronic valve).
Philips-Ideezet
This is the first Philips production type tube. In 1918 delivered on order to the Nederlandse Radio-Industrie (owned by H.H.S. à Steringa Idzerda ). The model remained in production till 1922.
Miniwatt
1923, types A110, A310
The emission improved considerably by replacing the bright emitter cathode by an oxide cathode.
Because of the reduced filament current Philips introduced the trade mark “Miniwatt”.
Pentode
1926. Types B443, D143
In the Philips Research Laboratories ir. B.D.H. Tellegen developed the five electrodes valve, called the pentode.
The addition of the suppressor grid improved the operation of the tetrode considerably.
It was used in de power stage of the first Philips receivers 2501 and 2502
(1927).
Octode
1934. Type AK1
Golden series.
This is a tube with 8 electrodes, designed for the mixing stage of the super heterodyne receiver.
Red E-series
1936.
For use in car radio the filament voltage was increased till 6.3 volt.
The base has the contacts on the side.
Loctal valve
1939. Type EF50
This is a high frequency pentode.
It is a special type of the loctal base tube with 9 pins.
The construction has a base of pressed glass with short pins. This reduced the length of the internal wiring. So it became suitable for television and ultra shortwave reception.
At the beginning of the war all the production facilities where smuggled from the Netherlands to England. It played an important role in military radar equipment.
Loctal tube
1940
This is the standard locktal base tube with 8 pins for use in commercial receivers.
Very compact receivers could be constructed with this tube, like the 203A “Philetta” in 1941.
Rimlock-valve
After the war came the Rimlock tube (r). This is a small glass tube with 8 pins
and a locating pip on the side.
Noval-valve
The Noval tube (l) has 9 asymmetrical positioned pins.
In 1953 it was introduced as a NATO standard.
