mosfet
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Jan 17, 2013, 3:29 PM
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How to test Schottky diode
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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.
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