Billions.
no, second generation. third generation computers used ICs.
They haven't been replaced! Only now they are much smaller and switched on and off by nano-bots that receive instructions from user input.
Early transistors were much slower and far more expensive than vacuum tubes. Also computers built before 1948 there were no transistors to use at all.
Tubes, magnetic logic, and transistors.
Transistors have two basic functions: # an electrically controlled electric switch # an electrically controlled "proportional valve" which can alter currents and voltages, or can amplify electric signals. Transistors can also be configured as Oscillators which provide an AC signal with constant frequency. Either an amplifier circuit or a switching circuit can be wired as an oscillator. Transistors can be used to form logic gates: And, Or, and Invert. Computers are made from logic gates, so computers can be made entirely from transistors. Transistors are in use in virtually all electronic devices. PC processors are composed of millions of tiny transistors. A transistor radio may have had only 6-10 transistors to enable operation. A late model car may have 10 to 15 computers comprised of thousands of transistors to perform all manner of operations in the vehicle.
The lowprice and flexability of modern computers allow many businessesandorginizations to place terminals in many differentlocations.
Several early digital computers were made of electromechanical devices similar to those used to build automatic dial telephone exchanges used at the time. First generation digital computers were made of vacuum tubes. Second generation digital computers were made of discrete transistors (most used germanium transistors but later some silicon transistors). Third generation digital computers were made of (hybrid, SSI, MSI, LSI) silicon integrated circuits. Fourth generation digital computers are made of microprocessors and other (VLSI, ULSI, etc.) silicon integrated circuits.
They could only perform basic calculations.
Digital computers use binary numbers because that is easier for them, and the easiest way for humans to represent what goes on inside of computers. Computers contain millions of transistors inside the various ICs in the computer. Transistors can generally be on or off. Sure, it is possible for transistors to have a range, but then, in this case, it wouldn't be digital. So since the transistors are used as on-off switches, it is easiest to represent them as binary digits, since they can either be on or off.
Second generation computers used electronic transistors. A small number used magnetic amplifiers.
integrated circuits
Just like the valves used in valve stereo equipment or old radios. Except in computers (like the transistors in modern computers) valves are usually driven fully into saturation and cutoff, while in a valve stereo or old radio valves are usually operated as linear amplifiers with minimal distortion.