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2 Layout and installation
Next, solder the LEDs. Push the blue LED into the hole
near the middle of the cardboard box and the green one into
the hole near the edge. Make sure of the correct polarity of
the LEDs! The longer LED lead (anode) has to be connected
to the soldering pad marked “+”, the shorter one (cathode)
to the soldering pad marked “-”. Bend the LED leads so that
they end in the middle of the respective soldering pad and
can be soldered comfortably.
Like any other semiconductor elements, LEDs are
sensitive to heat. When you do not have much experience
in soldering, it is best to wait a moment after you have sol-
dered the first lead of the component so that the compo-
nent can cool down before you attempt to solder the sec-
ond lead. If the LEDs are not sufficiently locked in position,
you can secure them additionally with a little all-purpose
glue.
Figure 2.3:
Push-buttons on
the circuit board
