800px-Carbon-resistor-TR212-1

Resistor

""I didn’t understand the resistor in the beginning.

It didn’t seem to do anything! It was just there, consuming power.

With time, I learned that the resistor is actually extremely useful.

You’ll see resistors everywhere. As the name suggests, they resist the current.

But you are probably wondering:

What do I use it for?

You use the resistor to control the voltages and the currents in your circuit.

How?

By using Ohm’s law.

Let’s say you have a 9V battery and you want to turn on a Light-Emitting Diode (LED).

If you connect the battery directly to the LED, LOTS of current will flow through the LED!

Much more that the LED can handle. So the LED will become very hot and burn out after a short amount of time.

But – if you put a resistor in series with the LED, you can control how much current going through the LED.

In this case we call it a current limiting resistor.""