A tutorial on the Zener Diode and how to use them as voltage clamps, voltage regulators, and how to create audio distortion circuits.
Circuit symbol 
Working of a Zener Diode
With a regular diode, current can only flow in one direction. But for the Zener diode, current can flow in both the directions.
The zener diode works as if there are two regular diodes in parallel, facing it in opposite directions each with different voltage drops. When you try to push current in the forward direction, there is a forward voltage drop which is typically around 1 volt. The diode will not turn on and allow current to flow unless you have at least 1 volt. And, when the Zener is on in the forward direction, we called it as forward biased. But going the opposite direction, there is a different voltage drop called as the Zener voltage or Vz. In the example given in the video, the Vz value is 3.3V. This zener will not allow current to flow in the opposite direction unless there is at least 3.3V across it. But when there is sufficient voltage, the current can flow in the opposite direction and you will get a constant voltage drop of 3.3V.
Since the current is flowing backwards, we say that the Zener is reverse biased. This property of having a predictable voltage drop is what makes Zener diode useful.
You can use Zener Diodes to limit the voltage that other devices received. Thus protecting your devices from high voltages.
The presenter has conducted simple examples in his video supporting the use of a Zener diode. He has explained the Classic Zener Diode Clamping circuit using 3.3V and another circuit with 5.1V.
Video Courtesy: Afrotechmods
Note:Â The above text is an abstract taken from the video tutorial given above.
