Project Hub /Test & Measurement Instrumentation/Component & Cable Testers/Accurate And Easy-To-Use Zener Diode Tester

Intermediate

ARDUINO

₹500 – ₹1,500

3 – 6 Hours

Partial Kit

Accurate And Easy-To-Use Zener Diode Tester

A DIY Zener diode tester designed with an ATmega328 microcontroller to test Zener and ordinary diodes up to 33V with high resolution.

Originally published on ElectronicsForU

View original tutorial

Parts You'll Need

This project is sourced from another site, not written by us — this list is our best match of their components against what we stock, not a verified bill of materials. Always check the original blog (linked above) for the actual parts list before buying.

LM2596 Step Down DC-DC Buck Converter Rs. 99.00
5V 1 Channel Relay Module Rs. 87.00
10pcs - 220 ohm 1/4 W Resistor Set Rs. 39.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

This list includes a generic resistor set as a placeholder — it is not matched to the exact value or part number this circuit needs. The correct one is specified on the original source page linked above; check it before buying.

We don't carry yet: ATmega / AVR chip
Transformer
Diodes (1N4007 / 1N4148 / Schottky / Zener)
Transistors (BC547 / 2N2222 / TIP / MOSFET)
Op-Amp IC (LM358 / LM741 / TL072)
Potentiometer / Trimpot
Capacitors
Magnets / Electrodes / Probes

Browse all components

How It Works

The Accurate And Easy-To-Use Zener Diode Tester evaluates Zener and standard diodes by applying a controlled variable DC voltage up to 33V across test probes. The power subsystem begins with a mains-connected transformer TR1 (stepping down 230VAC to 36VAC), which feeds a bridge rectifier BR1 and filter capacitors (C3, C4, C5) to produce an unregulated DC rail. A DC-DC converter module (U13) regulates voltage levels for the low-voltage control circuitry. The heart of the system is an ATmega328 microcontroller (hosted on the Arduino Uno platform), which manages the test cycle. Relays (RL1, RL2) driven by transistors (Q1, Q2) dynamically switch circuit paths and isolate the high-voltage test terminals during idle states. Diodes D3 and D4 provide necessary flyback protection and signal clamping. An operational amplifier (U1) conditions the analog voltage signals dropped across the device under test, interfacing with resistive networks and a trim potentiometer (RV1) for calibration. The ATmega328 reads these conditioned analog values via its built-in analog-to-digital converter, computing the exact breakdown voltage of the Zener diode with high resolution. Users write and upload firmware via the Arduino IDE to control the automated testing routine and display results.

Why Build This

Design and characterize custom power supply regulation stages by accurately verifying Zener diode breakdown voltages up to 33V.

Implement automated relay switching and transistor driver circuits controlled by an ATmega328 microcontroller for safe test-bench operations.

Deploy practical analog signal conditioning techniques using operational amplifiers and trim potentiometers for precision measurement.

Real-World Application

Quality control, R&D units, educational laboratories, and electronics repair shops for testing and matching Zener diodes.

Skills You'll Learn

Microcontroller-based measurement

relay switching control

transistor driver design

operational amplifier signal conditioning

DC-DC power conversion

analog-to-digital voltage sampling

microcontroller firmware development

Safety Precautions

Exercise caution when dealing with mains AC voltage (230VAC) in the power supply section.

Technology Tags

MICROCONTROLLER

ATMEGA328

ZENER DIODE

TESTING

POWER SUPPLY

RELAYS

OP-AMP

Frequently Asked Questions

What is the maximum voltage this tester can handle?

The tester is designed to evaluate Zener and ordinary diodes up to 33V using its regulated test voltage supply.

Can I use a standard Arduino Uno board for this project?

Yes, the system is built around the ATmega328 microcontroller found on the Arduino Uno platform, programmed via the Arduino IDE.

Do I need to worry about the 230VAC mains connection?

Yes, transformer TR1 steps down 230VAC mains voltage; proper insulation and caution are required when working around the power supply stage.

Gallery

This page is part of Kitkraft's Project Hub — a curated collection of electronics & robotics projects gathered from the maker community to help students and hobbyists discover and learn to build. Kitkraft does not claim authorship of the original project, and makes no representation as to the accuracy, completeness or safety of third-party source material. The summary and "How It Works" explanation above are AI-generated, rewritten with reference to the original tutorial — not a reproduction of it. Full credit and a direct link to the original source are provided above. If you're the original creator and have a concern about how your work is represented here, please contact us and we'll address it promptly.

Kitkraft Project Hub — curated from the maker community, credited at the source.

PRJ-00719