Zener Tester





We will create an electronic device to test the zener diode voltage.

First , Theoretically we will learn how the Zener diode work?

Let's get started

Step 1: How the Zener Diode Work?

The first thing to know is that the circuit symbol for zener diodes looks very similar to other diode symbols.

Make sure you don't get them confused because they behave very differently, and they are used for very different things! So what's special about zener diodes?

Regular diode VS Zener diode:

Step by step we will learn how it works and how Zener diode current passes in two directions?

Zener diodes work exactly like a standard diode, with the exception of one thing.

When the zener is on in the forward direction, we say it is "forward biased".

The diode won't even turn on and allow current to flow unless you have at least 0.7 volt with silicon diode and 0.3 volt with germanium diode.

But going the other way, In reverse biase.

Since current is flowing backwards, we say the Zener diode is "reverse biased". This property of having a predictable voltage drop is what makes Zener diodes useful.

Step 2: Three Ways to Measure Zener Diode Voltage

This simple circuit show you how to measure the Zener diode.

•The easiest way to measure the Zener voltage as shown by connecting 1K Ohm in series with the Zener diode.

•The battery or power supply must be larger than the voltage rating of the diode.

I have used 30 volts as a power supply to the circuit.

The second circuit i used a 30V transformer as a power supply.

the third circuit i used ( 3.7 Li-Ion battery + charger + DC-DC boost converter) as a power supply

Step 3: Step by Step How to Make a Device Measuring Zener Diode Voltage:

With photos and videos you can understand the steps of how to make a device measuring Zener diode voltage




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6 Discussions


11 days ago

What size in Watts is the 4.7k ohm resistor?


Question 5 months ago on Introduction

I built this nice construction and it works like a charm. Thanks for sharing.
I just want to know the role of LM317 in the circuit, when the output pin is shorted to Adjust pin.


2 years ago

nice and cnstructive project thanking you for shearing


2 years ago

Works like a charm! Thanks for sharing.


2 years ago

This can be a very useful device, thanks for sharing your concept. ☺