Construction
Preparation:
You should have a small tipped soldering iron, some thin (< 1mm, ideally 0.6mm) solder, and electronic
side cutters.
Components:
You should find the following contents as listed in the BOM (Bill of Materials). It is best to check the
contents before you start.
Please see the appendix to help you identify individual components.
Low Voltage Circuit:
Parts List:
D1
IN4001
C2
100nF
C3
220uF
C4
220uF
IC1
7805TV
R14
3k
LED1
LED3MM
SV1
CONN_POWER
The Low Voltage circuit is a very traditional voltage regulator using a linear regulator. It's job is to reduce
the external voltage from the power adapter down to a known and stable 5V to drive the micro-controller
and the 74141/K155ID.
Put the parts on the board in the marked locations in the order they appear on the list.
Notes:
•
See the section on “Component Identification” for help with identifying the components.
•
D1 and D2 look very similar, but have different jobs to do. Be careful to get the 1N4001 and not the
UF4007.
•
D1 should be placed so that the white stripe on the body lines up with the white stripe on the
board.
•
C3 and C4 must go the right way round. The negative side is marked with a stripe. (See hint)
•
The LED must go with the right polarity. The side which has the shorter lead goes nearest the
diode. (See hint)
•
Put IC1 so that the metal tab lines up with the white stripe on the board. The metal side faces to
the
outside of the board.
