7
Insert the transistor, the
potentiometer and the IC as
shown in the picture. Ensure
the transistor
’
s flat side
matches the outline of the
silkscreen. Ensure the notch of
the IC aligns with the markings
on the board, also known as
the silkscreen.
Please pay attention to the labelling of the transistors as one is an SS9012 and
the other is SS9013. They both have different functions and must go in the
correct place for this circuit to work!
Insert the 4-pin header,
the piezo buzzer and the
MQ sensor onto the board
and solder them as shown
in the image. Ensure that
the buzzer
’
s positive lead
(+) is facing down.
It is recommended to
solder the MQ2 element
with the label facing
inwards towards the
resistors.
