Do you recognize a modern electronic device in this
"lamp"? In fact, this is the first triode produced by
Philips in 1917. It was not the company's idea to step into
electronics: they were asked to develop a detector-lamp by a
Dutch radio pioneer,
the engineer Schotanus à Steringa Idzerda.
He was probably the first person worldwide to transmit music programs on a regular basis, for which he made announcements in the newspapers. The first transmission of this kind could be heard in November 1919.
A few thousands were manufactured and the price at the time
was 12.50 guilders. I'm proud to have one in my collection!
There are stamps on both ends. On the one end the stamp reads
"P 25-30V", this must be the plate voltage. On the
other end: "0.5amp max.4V" for the filament.. Overall
length = 118 millimeters. And indeed, the thread on both sides is
the regular E14 as used for small light bulbs.
