Vectronics VEC-1120K - Manual (Page 7)

VEC-1120K/1130K/1140K/1180K Instruction Manual
5
Transistors:
If transistors are installed incorrectly, damage may result when power is applied.
Transistors in metal cases have a small tab near the emitter lead to identify
correct positioning. Semiconductors housed in small plastic cases (TO-92) have
an easily-identified flat side to identify mounting orientation. Many specialized
diodes and low-current voltage regulators also use this type packaging. Larger
plastic transistors and voltage regulators use a case backed with a prominent
metal tab to dissipate heat (T-220). Here orientation is indicated by the
positioning of the cooling tab.
Emitter
Flat Side
Metal Tab
Metal Can Device Plastic Device Tab-cooled Device
Integrated Circuits:
Proper IC positioning is indicated by a dot or square marking located on one end
of the device. A corresponding mark will be silk-screened on the PC board and
printed on the kit's parts-placement diagram. To identify specific IC pin
numbers for testing purposes, see the diagram below. Pin numbers always start
at the keyed end of the case and progress counter-clockwise around the device,
as shown in the following diagram.
1 2 3 4
8 7 6 5
Installation
Key
Key
Installation
Pin Numbers
PARTS LIST
Your kit should contain all of the parts listed below. Please identify and
inventory each item on the checklist before you start building. If any parts are
missing or damaged, refer to the manual’s warranty section for replacement
instructions. If you can’t positively identify an unfamiliar item on the basis of
the information given, set it aside until all other items are checked off. You may