What is Polarity

You’ve probably heard the word polarity in relation to magnets. Magnets have a positive and negative side. The opposite sides attract one another while the same sides repel each other.

Electricity also has polarity. Like magnets, it has positive and negative poles. Have you ever looked at a battery and noticed that one end has a plus sign and the other end has a minus sign? These represent the electrical polarity.

Electrical polarity determines which way the electrons will flow. Electrons flow from the negative side to the positive side. Have you ever put a battery in the wrong way? Your device didn’t work. That’s because the electrons couldn’t flow because the poles were in the wrong direction.

In circuits, the positive wire is red and the negative wire is black.  When using components such as buzzers and motors, match the wire colors.

LEDs also have polarity. If you look closely, you'll see the terminals are slightly different sizes. The longer terminal goes into the red battery pack wire and the shorter goes to the black battery pack wire.

Quick Recap:
LEDs have polarity - the longer terminal goes to the red battery pack wire.
Buzzers have polarity - the red wire matches the red wire of the battery pack.
Motors do not have polarity - switching the wires will change the motor's rotation.
Switches do not have polarity - they simply allow electricity to pass through or not.

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