Science & TechnologyGreek → English
Pentode
/ˈpɛntoʊd/noun
A vacuum tube with five electrodes, giving higher gain and better isolation than a triode.
The Greek roots
πέντε
pénte
five
ὁδός
hodós
way, road
Literally: “five ways”
The story of the word
Bernard Tellegen and Gilles Holst added a fifth electrode at Philips in 1926, a suppressor grid whose job is to bat back electrons that bounce off the anode and would otherwise ruin the signal. The name follows the pattern set by diode and triode, all of them counting Faraday's ὁδός, the road the current takes. Greek πέντε is the same five as in pentagon and Pentecost, the fiftieth day.
- How it travelled
- Ancient Greek → scientific coinage → English
- First recorded
- 1920s
Same family
triodediodepentagonelectrode
In a sentence
The old radio uses a pentode in the output stage, which is why it needs half an hour to warm up properly.