The L.E.D. Closeup.
When
a small current flows through an L.E.D. (normally
about 20-30 milliamps) it will light up. Unlike an ordinary bulb,
its two connections ( + and -) must be connected correctly to
the power source for it to work.
The
two different connections to the L.E.D. are :
1, The Anode (+)
2,
The Cathode (-).
These
can be identified by looking for either the long (+) or
short (-) legs. The flattened edge of the led is always nearest
to the Cathode (-). Please look carefully at the image above
to see this.
Getting
it working
L.E.D.'s are semiconductors and most of them cannot work
safely in a circuit on their own. This is because they allow too
much current to flow. Unlike the light bulbs that takes only the
current it needs to work.
To
protect the L.E.D., it is necessary to use an electronic
component called a resistor. This is connected in series with it.
Please go on to the next link
to find out about this.
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