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shop.itaca-innovation.com uChip Kit user manual
In our kits, you will find only two types of resistors:
-Carbon Resistors (like the example on the left). These have typically a brown-beige color, and they
have only four bands. In our case, the last band is always gold-colored (when not specifically specified
in the project), indicating a 5% tolerance.
-Metal film resistors. These resistors are blue (like the resistor on the right), and have 5 colored bands.
The last band is always brown, as metal-film resistor provided in uChip Kits have a 1% tolerance.
Note! While for carbon resistors it is very easy to determine which band is the first one, and which one is the
last (the gold one!), on metal film resistor, sometimes the bands are too tightly packed to clearly identify which
one is the last. In fact, in many cases, both the first and the last color of the band might be brown (think of a
1% 1.5 kOhm resistor –brown –green –black –red –brown, which might be confused with a 12 MOhm
resistor: brown, red, black, green, brown !).
At this regards, the quickest way is to use a multimeter to get the resistance value (be aware of the tolerance!
A 1% 10kOhm resistor might read as low as 9.9 kOhm or 10.1 kOhm–you must then consider your multimeter
tolerance, therefore you might read even smaller or higher values!).
Another way is to decode the bands in one direction, and try to find the decoded value in the BOM list (the
BOM list also include the color sequence, so you do not have to manually decode the values!). If you cannot
find the resistor in the BOM, then you should read the resistor in the opposite direction.
Yet another way, is to use common sense! Let us consider a 18 kOhm resistor. This has brown, grey, black,
red, brown bands. If you decode those bands in the opposite way, you would achieve 120 * 108Ohm = 12
GOhm. While this value is still standard, it is insanely huge, and very unlikely that such a resistor would be
included in our kits!
Still, there might be some cases in which the value is “reasonable” when you read the color code in both ways.
In particular, with the 15 kOhm example, both 15 kOhm and 12 MOhm are quite reasonable values. However,
uChip Kits are designed so that in such case there would be either just 15 kOhm resistor, or 12 MOhm resistor,
but not both values!
CAPACITORS
There are fundamentally two types of capacitors. Polarized (electrolytic capacitors) and unpolarized (ceramic
disc capacitors, polyester capacitors, etc.).
Electrolytic Capacitors
EXTREME care should be paid to put the capacitor with the correct orientation, otherwise they will heat-up
and they might even explode.
In such capacitors, the capacitance value and the working voltage are explicitly written on the side of the body.
Furthermore, the negative terminal (typically the shorter one) is shown as a strip of minus (“-“).
