Raspberry Pi A, User Manual, Page: 223 / 314

C H A P T E R 1 3
L E A R N I N G T O H A C K H A R D W A R E
207
Figure 13-1:
A four-band
resistor and the
decoding table
for its colour
code
To read the example resistor, first take the two resistance bands starting from the left: these
are coloured red and red. Red, on the table included in Figure 13-1, equates to the value 2, so
the initial reading is 22. The next band is green, which is the multiplier and equates to 10
5
or
100,000 (10 followed by five zeros). Multiplying 22 by 100,000 equals 2,200,000, which is
the resistance value in ohms: 2,200,000
Ω
.
There are 1,000 ohms in a kiloohm , and 1,000 kiloohms in a megaohm. Thus, 2,200,000
Ω
would typically be written as 2,2 M
Ω
. The final band, located on the right side of the resistor,
is gold and details the tolerance, or accuracy, of the resistor, which is plus or minus 5 percent
in the example shown in Figure 13-1.