Protect Your Circuits!

Here are a few circuits that show how diodes work. These are basic examples of reverse polarity protection. If you have ever connected something backwards on your breadboard, you know it can lead to disastrous results!

Lets review what a diode does at its core: it allows current to go only in one direction. This is useful when you do not want to worry about current going backwards or in the opposite direction. Think of it like a 1 way road or a water slide, you can only go down a slide not back up.

Lets also remember LEDs are diodes! They are light emitting diodes. These circuits work due to the diodes (the 1N5817 and LEDs) we use.

The best way to understand this circuit is to build it! You will immediately understand how current is flowing through the circuit. Swap the power supply positive and negative a few times and you will see the results.

You will need a few things depending on the circuit:

• [2] LEDs
• [2] 1N5817 Diode
• [2] 220Ω Resistor
• [2] 1KΩ Resistor
• [1] 5 Volt Motor
• [1] 5 Volt Battery
• [1] 9 Volt Battery
• [1] Breadboard

Some technical notes. Forward Voltage is the voltage needed to turn a diode on; Also diodes have a limit to how much current pass through them. You can find useful info on the diodes you have using datasheets. This will allow you to make your own designs using them.