Answer:
The vacuum tube was replaced with transistor.
Step-by-step explanation:
- The invention of semiconductor was very useful in making solid state transistor that allowed the production of small yet faster, cheaper, and more trusted and reliable computers.
- These solid state transistor is so often used that, it nearly replaced all the use of transistor.
- This replacement took place after the invention of semiconductor in the year around 1940.
- Vacuum tubes also known as thermionic tubes are not used anymore in computers and electronics.