I've been studying about diodes and transistors and something made me wonder about the purpose of transistors.

In the examples we were talking about increasing current by using two batteries with a transistor and I understood how the transistor transfers the current from one side to another while increasing it with another battery connected to both sides(probably I still have gaps with my knowledge).

But the problem is: I didn't understand why we need transistor to increase current, can't we do the same thing by just connecting two batteries together or just using a transformator to increase voltage to get more current or just simply using a bigger battery?

Maybe I'm thinking so straight logic now but examples did not look satisfying to me to understand the usefulness of transistors as I know how widely they are used especially in computer science (which is I'm interested and planing to study in university.) so I would like to hear better examples with explanations.


closed as off-topic by John Rennie, Qmechanic May 25 at 16:48

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  • 1
    $\begingroup$ Would Electrical Engineering be a better home for this question? $\endgroup$ – Qmechanic May 25 at 10:22
  • $\begingroup$ Well I was thinking to ask there but I'm not studying Electrical Engineering so I wasn't sure. $\endgroup$ – E.Berk May 25 at 16:46
  • $\begingroup$ This question definitely seems suited for electrical engineering (but I can't comment on whether it's a duplicate of one already there) $\endgroup$ – immibis May 27 at 5:17

Although there can be a current gain (and voltage gain) between the input and output of a transistor the important thing is that the (large) output current (and voltage) can be controlled by (small) input currents (and voltages).
This control of the output by the input can even be such that the transistor acts like a switch being turned on and off by the input current/voltage without using very much electrical power and this is the basis of the operation of a computer


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