Electronic components: Resistors

By Flavio Copes

An introduction to resistors in electronics: how they limit current, how color bands encode the resistance value, and the difference from variable resistors.

A resistor is a conductor component that has a certain amount of resistance.

We have a lot of different resistors, build with various materials, and with different resistance values. For example in my set I currently have:

• 10Ω
• 220Ω
• 330Ω
• 1kΩ
• 2kΩ
• 5kΩ
• 10kΩ
• 100kΩ
• 1MΩ

Each of those values has a different color combination, in order to let us identify the resistance value.

Reading the color is a skill on its own, and there are online calculators that help you with that, like this one.

Those above are fixed resistors, with a fixed resistance value.

Some other resistors which we’ll see later can let the users change their resistance (potentiometers), some change their resistance depending on the temperature (thermistors), light (photoresistors), and so on.

We’ve seen how a resistor can limit the amount of current flowing in a circuit in the post with the LED and the battery circuit.

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