From the course: Raspberry Pi: GPIO
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Protecting GPIO input with Zener diodes
From the course: Raspberry Pi: GPIO
Protecting GPIO input with Zener diodes
- [Instructor] Zener diodes are specially built to open a channel for excess voltage. They are ranked for different voltages so if you have a 3.3 volt zener diode connected to ground anything above 3.3 volts is shunted around from the raspberry pi, very convenient. For an in-depth discussion of zener diodes I recommend the zener diodes segment of Barron Stone's "Electronics Foundations: Semiconductor Devices". Let's take a look at a real world example. What you're looking at is a demonstration circuit of how a zener diode can protect the raspberry pi from over voltages. I have five volts coming in to the breadboard, I have a 22 ohm resistor, a push button, and a voltage gage. When I push the push button, you can see that I apply five volts. That five volts is being measured at the far end of the resistor. Now I'd like to connect the raspberry pi to that signal so I can tell when the push button is pushed. But five…
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