electronic repairs

Testing Schottky Diode- The Right Way To Test It.

 

is schottky diode or schottky barrier rectifiers are designed for
high efficiency rectification essential for applications like
Switched mode power supplies (SMPS), Switching regulator and
etc. If you look at electronic schematic diagram, schottky diode
symbol looks the same as normal diode. Even the shape and
designed just like a normal diode. The major differences
between a normal diode and schottky diode is the part number.
Due to this, many technicians thinks that checking schottky diode
just the same as checking a normal diode. Infact there is a right
method to identify schottky diode and a suggested way to test it.

Searching the internet for the diode schottky part number and browsing
through the semiconductor replacement guide can quickly give
you the answer whether the component that you are testing
is a normal diode, ultra fast recovery diode or schottky diode.
If you have confirmed that the diode is a schottky diode then you
you have to use the accurate way to test it.

Set your analog multimeter to times 10k ohm. Place the red probe
to the cathode and the black probe to the anode. You should see
the needle goes up to full scale. Reversing the probe will show
some leakage which mean the needle move up a little bit. This is
a good schottky diode characteristic when checking on it. However
if you measure a normal diode and you discovered that it has
two readings then the diode is considered spoilt and need to replace.
A shorted schottky barrier diode will show two full scale readings
registered at the panel meter. 

 

is a technician do not know how to check a schottky diode, he or she
may think that the diode have some leakage and need to replace. The
worst part is diodo schottky is not easy to find in the market.
Searching for schottky diode replacement will take you time and
it is not necessary if you know how to test it. The technician might
just simply replace a 'normal diode' and hope that it will work.
Well, the equipment will still not work because you have replaced
a working diode (schottky diode) with another good diode! The actual
culprit is still out there and not the schottky diode.

Sometimes replacing a schottky diode with a normal diode may cause
the equipment to be unstable especially in the sensitive circuit. The
best is to replace with original number or a specification that is
higher than the original diode. Typical part number for a schottky diode
is 1N5819. Go check out this part number from your favorite search engine
and semiconductor data book.

That's it for this issue my friend. Thank you for reading. I will send
you more tips. Until then, here's wishing you all the best in
electronic repair.