This post describes our initial attempt to design an automatic Zener diode tester. This tester is designed using well-known ICs such as MC34063 and PIC16F88.
This unit is capable of identifying Zener diodes up to 27.5V. Apart from that, it can be used to recognize leads of the diodes/Zeners and detect damaged diodes.
For this project, we use components that are already in our inventory. Most of these components can be replaced with more accurate and modern substitutes.
This unit provides approximately 5% to 15% accurate readings. Based on our observations, the accuracy of this unit can increase by using resistors with 1% tolerance, stable booster circuit, accurate sampling method(s), and with a more optimized PCB layout.
The schematic, PCB design and firmware of this project are available to download at github.com.
