The first computer to be programmable was the Z3. Kondrad Zuse designed the Z3 so that the Germans could use secret codes during the Second World War.
The First Computer in the Modern Sense: ENIAC
This computer was developed in the Second World War. It is considered to be the first modern computer built. It was produced for the purpose of calculating the coordinates of the place where the bombs would fall during the war. ENIAC was able to calculate the result in 30 (thirty) seconds, which a person on the subject could calculate in 20 (twenty) hours. It consisted of 18000 vacuum tubes and 5 million additional components soldered by hand. It covered a large room with a mass of 30 tons and a volume. It was consuming as much electrical power as 50 (fifty) houses of that time used. When viewed from the outside, the computer had piles of cables and multiple flashing lights. Operators using this computer were using the existing 6000 mechanical switches for command input.
Post 1950s
Transistors have replaced the previously used vacuum tubes. Then, integrated circuits and microprocessors were invented that allow electronic circuit elements (diode, resistor, capacitor, transistor, etc.) to be placed on a silicon chip. After this stage, the volume of computers shrank. The computer mouse with two metal wheels and a wooden box was put into use in 1960. Only people with expert knowledge were able to use the first computers. The first personal computer (PC), named the Altair 8800, was released in 1975. A television served as the monitor for this computer. Numerous companies introduced easy-to-use and inexpensive computers in the years following 1975. Then, peripherals that computers could use were produced. For example; printer, screen, keyboard, floppy drive etc. The Osborne 1 was released in 1981 as a portable computer. This computer weighs about 11 kg. mass, 64 kilobytes of memory, 5 inch screen and 2 (two) floppy drive capacity.
Source:
https://bilimgenc.tubitak.gov.tr/makale/bilgisayar-kim-ne-zaman-icat-etti#:~:text=Modern%20Anlamdaki%20%C4%B0lk%20Bilgisayar%3A%20ENIAC&text=%C4%B0kinci%20D%C3%BCnya%20Sava%C5%9F%C4%B1%20s%C4%B1ras%C4%B1nda%20geli%C5%9Ftirilen,nereye%20d%C3%BC%C5%9Fece%C4%9Fini%20hesaplamak%20i%C3%A7in%20%C3%BCretildi.
