Resistance Quick Reading Method OF Resistance Value

Three or four color ring resistor

The first two color rings represent the first two digits of the resistance value in ohms. On a 3-ring or 4-ring resistor, a third color ring indicates the magnification. This multiplier can change the position of the decimal place to represent any order of magnitude from megohm to milliohm. The fourth color ring represents the tolerance. Remember that if the 3-ring resistor does not have this color ring, the default tolerance is ±20%.

5 ring or 6 ring resistor

High-precision resistors also have a color ring to represent the third significant digit. If your resistor has 5 or 6 color rings, then the third color ring is this color ring, combined with the first and second color rings to represent the number. Continuing to the right, the fourth color ring represents magnification and the fifth represents tolerance. 6-ring resistors are basically of the same type as 5-ring resistors, with an additional color ring indicating reliability, or temperature coefficient (ppm/K) specifications. Taking brown, the most commonly used color in the sixth color ring, for example, every 10°C change in temperature results in a 0.1% change in resistance value.

Common questions about resistor color codes:

How do I tell which end to start reading the resistor?

? For many resistors, some of the color rings are more closely spaced or concentrated at one end. Hold the resistor in your hand so that these clustered color rings are on the left side. The resistor information is then read from left to right.

? The leftmost part of the resistor can never be a metallic color ring. If the color ring at one end of the resistor is gold or silver, the resistance tolerance is 5% or 10%. The resistor is placed so that the color ring is on the right, and again, the resistor's information is read from left to right.

? Common resistors range from 0.1 ohm to 10 megohm. It follows that the third color ring of a 4-ring resistor is always blue (106) or a color representing a lower value, while the fourth color ring of a 5-ring resistor is always green (105) or a color representing a lower value.

Why doesn't my high voltage resistor have a metallic color ring?

On high voltage resistors, yellow and gray replace gold and silver to avoid metal particles in the surface coating.

What is a zero ohm resistor?

The zero ohm resistor is easy to identify, with only a black color ring, which basically acts as a circuit wire to connect the wiring on the printed circuit board. They are packaged in a similar way to resistors, so the same automated equipment used to place resistors can also be used to place them on the circuit board. 

This design eliminates the need to install jumpers with other equipment.

Is there a trick to remembering the order of colors in a chart?

Although there are some methods on the web to help you memorize the resistor color code table, the results are mixed. Another color list memory method is to treat black as nothing, that is, "0", and white as a combination of all colors, that is, the highest value of "9". In the middle of the color chart, 

you will see the standard rainbow colors in order to represent the numbers 2 to 7, where your childhood ROY-G-BIV (red, orange, yellow, green, blue, indigo and violet) comes in handy, but without the indigo. You just need to remember that the brown between black and red represents "1", 

and the gray between purple and white represents "8", and you're done!

What is the "reliability" color ring?

The 4-ring resistors in military resistors usually have an additional color band to indicate reliability, or failure rate (%) per 1000 working hours. This is rarely seen in commercial electronics.

History of resistor development

Resistors are the basic components in a circuit. After testing the conductivity of various materials and discovering the existence of electric currents, early scientists gradually developed the concept of resistance. Scientists have found that copper, gold, and aluminum are good conductors with very low resistance,

 while air, mica, and ceramics are considered resistors because they greatly limit the flow of electricity. Although the industry has long known about its resistance properties, reliable resistors as we know them today didn't exist until 1961, when Otis Boykin created the first inexpensive, reliable resistor, 

and scientists were able to precisely control the amount of electricity transmitted to a component. Thanks to his breakthrough, resistors are much less susceptible to extreme temperatures and oscillations, eventually making their low-cost production possible. As the US Army, 

IBM and a host of consumer electronics manufacturers placed orders for Boykin's new resistors, they found their way into everything from home appliances and computers to guided missiles.

Resistors are ubiquitous in today's electronics. As passive devices, they consume but never provide energy. They have a wide range of uses in circuits, such as regulating the current input to leds or controlling the total voltage transmitted to active devices such as transistors. 

Resistors can be used to block transmission lines and prevent reflections, or they can also be used as pulle-up or pulle-down resistors in a microcontroller GPIO to enhance system stability. The combination of resistors and capacitors can create the timing source necessary for flash lights or electronic alarm circuits.

 A "Daisy chain" of resistors in series can act as a voltage divider, which is useful for components that need to operate below the input voltage.