Answer:
Transistor
Explanation:
It was Transistor that replaced the Vaccum Cube. Another Fan fact I want to give you thate , after invention of this, one of the reputed computer manufacturer of the world HP was founded. The fun is that this consists of two people name. Hawward and Paker. They TOSSED COIN TO SELECT THEIR CONOANY NAME ( to determine haward will go before the name or pakar. )