|
|
|
|
|
 |
|
|
|
|
Resistor and Flexible Resistor Color
Codes |
|
|
|
A First
Figure
| B Second
Figure
| C Number
of Zeros
| D
Tolerance
|
|
| 0
|
| 0
|
| 0
|
|
|
|
| 1
|
| 1
|
| 1
|
| 1%
|
|
| 2
|
| 2
|
| 2
|
| 2%
|
|
| 3
|
| 3
|
| 3
|
| 3%
|
|
| 4
|
| 4
|
| 4
|
| 4%
|
|
| 5
|
| 5
|
| 5
|
| 5%
|
|
| 6
|
| 6
|
| 6
|
| 6%
|
|
| 7
|
| 7
|
| 7
|
| 7%
|
|
| 8
|
| 8
|
| 8
|
| 8%
|
|
| 9
|
| 9
|
| 9
|
| 9%
|
|
|
|
|
|
|
|
| 5%
|
|
|
|
|
|
|
|
| 10%
|
|
|
|
|
|
|
| None
| 20%
|
|
|
The RMA System
|
|
|
|
The basis of the Resistor Color code system is
that all resistance values (in ohms) may be indicated by means
of a system of three colors painted on the resistor in the form
of narrow bands, dots, or as a body color. The percent of
tolerance in the resistance value may be indicated by a fourth
band of color.
Different manufactures adopted several different
convenient arrangements for marking these color bands and dots
on the resistors, but the same basis system applies to all of
them.
The system is as follows:
(1) the first figure of the
resistance value in ohms is represented by one of the colors.
(2) the second figure is represented
by another one of the colors.
(3) the number of zeros following
the second figure is represented by the third color.
(4) the percent tolerance in the indicated
resistance value is represented by the fourth color. Gold
= 5%, Silver
= 10%, and resistors rated at 20% bear no color bar.
|
|
Molded Fixed Resistors
|
|
 |
Figures 1 and 2
(1) the first figure of the resistance value in
ohms is indicated by the body color (A) of the
resistor. (2) the second figure is indicated by the
color of one end (B) of the resistor.
|
 |
(3) the number of zeros following the second
figure is indicated by the color of a dot (C) --Figure
1, or a band (C) ---Figure 2, at the center of the
resistor. When no center dot or band exists, it is to be
assumed that the dot, or band is of the same color as the body
and the number of zeros is judged from that color.
(4) The percent of tolerance of the resistance
value is indicated by another colored band (D) (either
gold or silver) at the other end of the resistor. In the
absence of the tolerance band, the tolerance value is assumed
to be +/- 20%.
|
|
Flexible Type Resistors
|
Flexible fabric-covered wire-wound resistors are also RMA coded by
three identifying colors, the same as molded resistors. The method
of identification is as follows:
|
 |
(1) the body color (A) represents the first figure
of the resistance value in ohms.
(2) the thickest thread (triple thread) color
(B) represents the second figure.
(3) the thinnest thread (single-thread) color
(C) represents the number of zeros following the two
figures.
If either the thick or thin thread is missing, it is assumed to
be there, carrying the same color as the body.
|
 |
The consecutive colored band arrangements shown in figures 4 and 5
are a later marking arrangement widely used on molded
resistor--especially those provided with axial-type pigtail leads.
In the marking arrangement shown in figure 4, the three (or four)
bands are arranged side by side with band (A) indicating the first
significant figure of the resistance value.
|
 |
The band arrangement shown in figure 5 differs only in the
position of the bands. Here, the three bands are located
off-center on the resistor with the starting band (A) nearest the
center. This really amounts to the same arrangement as figure 4,
with the bands shifted to the right so that the tolerance band (D)
is at the end. The band are read the same as figure 4,
consecutively--left to right.
|
 |
Some molded resistors look like small, narrow, mica capacitors.
These are ordinarily RMA color-coded by means of three identifying
colored dots placed as illustrated in Figure 6. These dots are
read in sequence A-B-C, in the same manner as explained for the
markings for Figure 4.
|
