Example of Schottky Diode
The Schottky diode or schottky barrier rectifier is designed for uses in high efficiency rectification essential for applications like switched mode power supply (SMPS) circuit, switching regulator and etc. If you observe any electronic schematic diagrams and layout, schottky rectifier symbol looks exactly the same as a normal diode.
Even the outlook, shape and designed just like a normal diode. The major difference between a normal diode and schottky barrier diode is the part number. Because of the same outlook, many electronic repairers thinks that measuring schottky diodes is just the same way as testing a normal diode. If you use the normal diode checking method to test on schottky diode then chances are high that you will not solve the problem.
You need to confirm first if the diode you are checking is indeed a schottky diode. You can confirm it by searching the part number from a databook or from the internet. A common schottky diode part number is 1N5817. If you have the databook or computer you can check for this part number.
In order to accurately test the schottky diode you need to set your Sunwa analogue multimeter to x 10 k ohm. Place the red probe to the cathode and the black probe to anode and you will get a low ohm reading. Now, reverse the probe and you will get some leakage reading. In other words, the meter pointer will move up a little bit sometime to the center of the scale. This is the good characteristic of a schottky diode when you get this type of reading. If you test a normal diode and you discovered that it has two readings then the diode is said to be defect and need to be replaced.
If the schottky diode is shorted then it will show two full readings testing either way. When comes to replacement or substitution always look for the schottky diode that have a higher ampere and voltage rating.
Testing Electronic Components Ebook By Jestine Yong