De Forest invented the Audion (see photo below), the first effective device for electrical amplification, which became the standard radio tube. It was a triode ... He had invented a detector circuit ...

Transistor use also allowed “instant-on” operation because there were no filaments to heat up. As for mobility, the typical portable tube radio of the 1950s was about the size and weight of a lunchbox ...

A next-generation dark matter detector has started operations ... You may like A 'cosmic car radio' could help scientists tune in to dark matter within the next 15 years Black holes could work ...