Page 51 - Testing Electronic Components

and also stop overheating, which could cause a fire. Sometimes though
there were lightning strike on an equipment, you will be surprised that
only fuse were damaged and not the power supply section or components.

There are two basic types of fuses which is the
fast acting and slow blow type. The fast acting
fuse will open very quickly when their particular
current rating is exceeded. This is very
important for analogue multimeter, which can
quickly be destroyed when too much current flows through them, for
even a very small amount of time.
Even if you are an experienced repairer, sometimes we do made mistake
by accidentally touching the probe to the testing points where it should
not be touch! The slow blow fuse has a coiled construction inside the
glass. Slow blow fuses are designed to open only on a continued
overload, such as a short circuit. The function of the coiled construction is
to stop the fuse from blowing on just a temporary current surge.

Don’t replace a slow blow fuse in place of a fast acting fuse because it
may not open fast enough to prevent components damage under a high
current condition. It’s not dangerous to substitute a slow blow fuse with a
fast-acting fuse, but it will probably open up unnecessarily every now and
then when the equipment is first switch on such as when you switch on a
Computer Monitor.

A blown fuse can indicate how severe the short circuit is.

There’s a secret for you, a blown fuse can indicate something about the
problem. If the glass case of the fuse appears clear or transparent, and if
you can still see the slight broken pieces of the fuse element, this means
that there’s no major short circuit in the circuit. Replacing the fuse with

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