In 1906, Lee de Forest developed a "triode" to amplify and convert alternating current to direct current, which played a major role in the development of which invention?
The ans is - Radio
Which singer invested in the Ampex company in 1947 (which developed North America's first commercial reel-to-reel tape recorder), was the first to pre-record his radio shows and to master his commercial recordings on magnetic tape?
What appeared in the Netherlands in 1608, developed by Hans Lippershey, Zacharias Janssen and Jacob Metius, and improved by Galileo in 1609?
What is the name for what is basically an induction coil whereby the voltage of an alternating current can be increased or decreased without changing the frequency?
