Component values are marked either as text as on large wirewound
components. For example 100W
5% 3W would indicate a 100 ohm resistor with 5% tolerance (95
– 105 ohms) with a power rating of 3 watts. The markings 1k2
1% 0W25 would indicate 1.2 kilo-ohms (1200 ohms) with a 1% tolerance
rated at ¼ of a watt. On some resistors especially very small
parts, like those used in surface mount only the value is given
as a code such as 473, The last digit is a multiplier and is
the number of zeros to be added to the first two digits to make
the value, in this case 47000 or 47 kilo-ohms.
The other method of marking is by using coloured bands on the
body of axial leaded components as shown in the resistor
colour code chart.
Resistors can be connected in a number of combinations to obtain
non-standard values. The most common arrangements are:
RTOT = R1 + R2 +