A companion speech amplifier and modulator were sold as accessories.
2.
The " PNP point-contact germanium transistor " operated as a speech amplifier with a power gain of 18 in that trial.
3.
They also installed a new 1000 watt transmitter with automatic frequency control and new speech amplifiers at their plant in Coytesville NJ . These upgrades improved the range and sound quality of their broadcast.
4.
While the device was constructed a week earlier, Brattain's notes describe the first demonstration to higher-ups at Bell Labs on the afternoon of 23 December 1947, often given as the birthdate of the transistor . what is now known as the " p n p point-contact germanium transistor " operated as a speech amplifier with a power gain of 18 in that trial.
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