Testing Coil- Secrets On
How To Test Coil Or Inductor With Analog, Inductance and Flyback
Tester
Testing coil
is very easy compares to checking three leads components such as
SCR, FET and etc. In general, a coil consists of many turns or wire
wrapped around a common core. The core could be made of iron or
even air.
When an
electric current passes through the coil, a magnetic field is
produced. A coil in some respect s acts just opposite a capacitor.
A capacitor blocks DC while allowing AC to flow through it; a coil
allows DC to flow through it while restricting AC current flow.
Another name for a coil is an inductor.
Coil or inductor can be
test using an analog, inductance or a coil meter such as the
dick smith flyback tester. A coil that is small in size, I
would usually just test it with analog meter and you could
check it on board too. Set your analog meter to X1 ohm and
place the probes across the small coil. The meter should show
some reading (or continuity) and this proved that the coil
winding is okay. Small coils seldom spoilt because it have
less winding compares to big coils where it could have many
turns of winding and chances for it to go shorted is very
high.
Testing bigger coil or
inductor such as the computer monitor B+ coil, you need an
inductance meter to find out the exact inductance value which
is in the unit of henry (h). From experienced using an
inductance meter to check coils to see if it good or bad is
not recommended because a shorted coil (shorted between
winding) could have a good inductance value and you would
miss out checking a bad coil. Unless you want to use the
inductance meter to calculate the reading and do rewinding,
looping and etc on that coil. I would only test a big coil
with dick smith flyback meter. Any shorted winding in it
could be easily detected by this meter.
Now is the
time to share my true case example- a computer dealer send me
a monitor for repair with power blink symptom. Usually I do
not straight away repair the monitor but I would first use
the flyback tester to scan all the major coils (smps,
flyback, b+ coil and horizontal deflection coil) before using
my digital or analog meter to do testing.
When measuring the B+
coil, the Led lights went off and it suppose to show at least
5 LED bars and above. Upon soldering out the coil, I did not
see any burn mark at the winding or loop and in fact it looks
shiny. Because I trust the meter, I opened up the winding and
to my surprised the internal winding had burnt into crisp but
the outer winding looks good indeed! A new B+ coil restored
the monitor to life.
By using a flyback
tester for testing coil, it has helped me to locate many
shorted coils in switch mode power transformer primary
winding, B+ coil, flyback transformer primary winding and
horizontal deflection coil. The flyback meter can even be
used to check the condition of ballast in fluorescent lamp
too!
Using Flyback
Tester To Test Flyback Transformer
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