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I have one small question. I know that after passing through a resister, current remains the same in an ideal situation. But then, why are resistors used to limit the amount of current in a load. Also there is potential drop in the resister but what difference does it make if it passes the same current. For example, in LEDs, flow of large current can destroy it, so they are connected to voltage source through a resister. But if the same current passes through resister what effect will introducing the resister have? I know I'm missing some basic concepts, could you also suggest topics to revise.

Thanks in advance for the help!!

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    \$\begingroup\$ The technical answer to your question is a combination of Kirchhoff's Voltage law and ohms law. learn.sparkfun.com/tutorials/… might be a good resource to explore \$\endgroup\$
    – BeB00
    Commented Jan 20, 2018 at 22:48
  • \$\begingroup\$ Welcome to EE.SE. Think of current as water flowing in a pipe, and the resistor as a kink or valve to limit the flow of water. In theory the absence of a resistor could allow infinite current flow, which would destroy devices or at least blow a fuse. Suggest you research into Ohms law, and look at more diagrams to understand why a resistor is where it is. \$\endgroup\$
    – user105652
    Commented Jan 20, 2018 at 23:23
  • \$\begingroup\$ The resistor shares some of the available voltage potential leaving less for the LED. The LED has less voltage drive and so draws less current. The resistor is usually selected to result in a safe maximum current for the LED. \$\endgroup\$
    – KalleMP
    Commented Jan 20, 2018 at 23:53
  • \$\begingroup\$ Aah ok, now that makes sense. Thanks everyone for the help. \$\endgroup\$
    – Shivam Dubey
    Commented Jan 22, 2018 at 23:52

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I think you're confusing different meanings of the word "same".

In a simple circuit - one with no branches - the current at any point in the circuit is the same as the current at any other part of the circuit. Current isn't "lost" in a resistor.

But if you add a resistor into the circuit, then it resists the flow of current, making the current drop. The current at any point in the circuit is still the same as the current at any other part of the circuit. But it's not the same as the current was before you put in the resistor.

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