We are Apogeeweb Semiconductor Electronic

WELCOME TO OUR BLOG

Home arrow Resistors arrow What is Resistor and How to Read Resistor Color Code

arrow left

arrow right

What is Resistor and How to Read Resistor Color Code

Author: Apogeeweb
Date: 23 Mar 2018
 5120
electronic component

Warm hints: The word in this article is about 3250 words and the reading time is about 18 minutes.

Introduction

This paper shows the comprehensive introduction of resistor which is one of the common electronic components. Resistance is the ability to impede the flow of electrons, that is, the value of resistance, the unit is "Ω". A resistor is a device that has a certain resistance to current flow. The resistor is usually referred to as a resistor. The resistor is mainly responsible for the current limiting shunt in the circuit, and can also form other functions with other components, such as the wave-out circuit, etc. Commonly used resistors are mainly divided into three main parts: ordinary resistors (resistance fixed), variable resistors (resistors can be continuously variable or fine-tuning), sensitive resistors (including special functions, such as a photosensitive resistor, thermistor, etc.).

How to Read Resistor Color Codes Fast

Catalog

Introduction

Catalog

I What is resistor

II The size of the resistor

III Classification of resistors

IV Uses of resistors

V Series and parallel resistors

VI Resistor Color Code

 6.1 4 band resistor

 6.2 5 band resistor

 6.3 6 band resistor

 6.4 Color code exceptions

VII Types of resistor

VIII The function of resistor

IX FAQ

I What is resistor

Resistance is one of the most common and widely used components in the electronics industry. Its English name is called Resistor, which is often used to express R. Its unit is Ohm, which is represented by the symbol "Ω". In physics, the resistance indicates the size of the conductor to obstruct the current. The greater the resistance, the greater the hindrance to the current. A resistance element is an energy dissipation element that presents a hindrance to the current.

II The size of the resistor

Electrical resistance of an electrical conductor depends on

  • > the length of the conductor

  • > the material of the conductor

  • > the temperature of the material

  • > the cross-sectional area of the conductor

and can be expressed as

R = ρ l / A

where

R = resistance of the conductor (ohms, Ω)

ρ = resistivity of the conductor material (ohm meter, Ω m)

l = length of conductor (m)

A = cross-sectional area of conductor (m2)

Usually, when a constant resistance is made, its resistance is determined. The calculation formula of resistance is: R=U/I. That's Ohm's law.

Example:

The resistance of 10 meter gauge 17 copper wire with cross sectional area 1.04 mm2 can be calculated as

R = (1.7 x 10-8 Ω m) (10 m) / ((1.04 mm2)(10-6 m2/mm2))

= 0.16 Ω

+168a

III Classification of resistors

There are different types of resistance. The material has a carbon film resistor, metal film resistor, cement resistor, Wirewound resistors; according to the function can be divided into thermistors, varistors, photosensitive resistance; according to power, 1/16W, 1/8W, W W 1W, integrant, etc. According to the accuracy, it can be divided into 0.1%, 1%, and 5%. When a temperature sensor is designed, a thermistor that is sensitive to temperature can be used to build the temperature of the circuit detection environment.

IV Uses of resistors

The main functions of the resistor in the circuit are shunt, current limiting, partial pressure, filter (combined with capacitor use) and impedance matching.

Shunt effect: two resistors in parallel together as two branches, will be the current road diversion, as shown below.

Uses of resistors

two resistors in parallel together as two branches

The current is I = I1+I2.

Current limiting function: resistor series can limit the size of branch current in the circuit, and prevent the load in the circuit from burning out.

Current limiting function

Current limiting function

Partial pressure function: after two series resistors are connected in series, the current flowing through two resistances is equal, but the voltage of each resistor is not equal, which is obtained by Ohm's law. As shown in the following figure.

Current limiting function

Current limiting function

Filter function: used in conjunction with the capacitor can be constructed as a filter, as shown in the following figure.

Filter function

Filter function

V Series and parallel resistors

The series and parallel resistors are the lessons learned in the middle school textbooks, and their typical circuit diagrams are shown below.

series and parallel resistor

series and parallel resistor

> Series: the resistance after series is equal to the sum of the resistors.

> Parallel: the reciprocal of the total resistance after the parallel is equal to the sum of the reciprocals of the resistors.

VI Resistor Color Code

Resistor Color Code

Resistor Color Code

Resistor values are often indicated with color codes. The color ring resistors indicate the parameters of the resistance according to the different colors of the surface. 4 and 5 color resistors are commonly used. The 4 color ring resistor is usually a carbon film resistor. It uses the front 3 color rings to indicate the resistance. Fourth points are used to indicate the error. The 5 color ring resistance is usually a metal film resistor, the 5 color ring ratio is 4 color ring, and the accuracy is higher. The 4 color indicates the resistance value, fifth representations. The color code is given by several bands. Together they specify the resistance value, the tolerance and sometimes the reliability or failure rate. The number of bands varies from three to six. As a minimum, two bands indicate the resistance value and one band serves as a multiplier. The resistance values are standardized, these values are called preferred values.

6.1 4 band resistor

The four-band color code is the most common variation. These resistors have two bands for the resistance value, one multiplier and one tolerance band. In the example on the left, these bands are green, blue, red and gold. By using the color code chart, one finds that green stands for 5 and blue for 6. The value is thus 56·100 =5600 Ω. The golden band means that the resistor has a tolerance of 5%.  The resistance value lies therefore between 5320 and 5880 Ω. If the tolerance band would be left blank, the result is a 3 band resistor. This means that the resistance value remains the same, but the tolerance is 20%.

Color

First Ring

Second Ring

Multiplier

Fair rate

Black

0

0

10^0

———

Brown

1

1

10^1

———

Red

2

2

10^2

———

Orange

3

3

10^3

———

Yellow

4

4

10^4

———

Green

5

5

10^5

———

Blue

6

6

10^6

———

Purple

7

7

10^7

———

Gray

8

8

10^8

———

White

9

9

10^9

———

Gold

———

————

10^-1

±5%

Silver

———

————

10^-2

±10%

 

6.2 5 band resistor

Resistors with high precision have an extra band to indicate a third significant digit. Therefore, the first three bands indicate the significant digits, the fourth band is the multiplying factor and the fifth band represents the tolerance. There are exceptions to this. For example, sometimes the extra band indicates failure rate (military specification) or temperature coefficient (older or specialized resistors).

 

Color First Ring Second Third Ring Multiplier Fair rate

Black

0

0

0

10^0

——

Brown

1

1

1

10^1

1%

Red

2

2

2

10^2

2%

Orange

3

3

3

10^3

——

Yellow

4

4

4

10^4

——

Green

5

5

5

10^5

0.5%

Blue

6

6

6

10^6

0.25%

Purple

7

7

7

10^7

0.1%

Gray

8

8

8

10^8

±20%

White

9

9

9

10^9

——

Gold

——

——

——

10^-1

±5%

Silver

——

——

——

10^-2

±10%

6.3 6 band resistor

Resistors with 6 bands are usually for high precision resistors that have an additional band to specify the temperature coefficient (ppm/K). The most common color for the sixth band is brown (100 ppm/K). This means that for a temperature change of 10 ˚C, the resistance value can change by 0.1%. For special applications where temperature coefficient is critical other colors

6.4 Color code exceptions

> Single black band or zero-ohm resistor. A resistor with a single black band is called a zero-ohm resistor. Principally it is a wire link with the only the function of connecting traces on a PCB. Using the resistor package has the advantage of being able to use the same automated machines to place components on a circuit board.

> Reliability band. Resistors that are produced according to military specifications, sometimes include an extra band to indicate reliability. This is specified in the failure rate (%) per 1000 hours of service. This is rarely used in commercial electronics. Mostly the reliability band can be found on four > Band resistors. More information about reliability can be found in the US military handbook MIL-HDBK-199.

Deviating colors. For high voltage resistors often the colors gold and silver are replaced with yellow and gray. This is to prevent having metal particles in the coating.

> 5 band resistor with the 4th band of gold or silver. Five band resistors with the fourth band of gold or silver form an exception and are used on specialized and older resistors. The first two bands represent the significant digits, the 3th the multiplying factor, the 4th the tolerance and the 5th the temperature coefficient (ppm/K).

VII Types of resistor

  • SMD resistor

SMD Resistors

SMD resistor

SMD resistors have the advantages of small volume, lightweight, high installation density, strong seismic resistance, strong anti-interference ability and high-frequency characteristics. They are widely used in computers, mobile phones, electronic dictionaries, medical electronic products, video cameras, electronic watt-hour meters and VCD machines. The patch components can be divided into three types, which are rectangular, cylindrical and heteromorphic according to their shape. There are resistors, capacitors, inductors, transistors and small integrated circuits. The patch elements are different from those of the general components.

  • Cement resistor

Cement resistor

Cement resistors

Cement resistance is a kind of rake resistance, usually put resistance into the square porcelain, with special non-flammable and heat-resistant cement filling and sealing, and the outer image is a cement block, so it is called cement resistor. Cement resistor with high power heat stability high moisture resistant seismic characteristics. It is mainly used in high power circuits, such as the overdetection and protection circuit of the power circuit, and the power output circuit in the audio amplifier is medium. The cement parameter is the direct standard method.

  • Array Resistor

Array resistor

Array resistor

The network resistor which is also called Wire-wound Resistor is a combination of several resistors that are exactly the same. One of their pins is connected together as a common pin. The rest of the pins are normally elicited. So if a drag is made up of a resistor, then it has an n+1 pin. Generally, the one on the left is a common pin. It is usually marked with a color point on the drag. It has many advantages, such as convenient assembly and high density. It has been widely used in TV, display, computer mainboard and small household appliances. Network resistor usually has a public side, with a white spot on the surface of said package. The color is usually black or yellow. The network resistor is generally applied to digital circuits, such as: as a pull or pull-down resistance of a parallel port. The use of the network resistor ratio is more convenient to use a number of fixed resistors. It is directional and has the advantage of neatly and less space than the color ring resistance.

  • Wirewound Resistors

Wirewound resistors are made by wrapping a high resistance wire, generally a nickel-chromium alloy, around a ceramic bobbin. By varying the diameter, length, and alloy of the wire and the wrap pattern the properties of the wire-wound resistor can be tailored to the application. They do suffer from high inductance and capacitance due to the nature of their construction, which limits them to low-frequency applications.

  • Metal Film Resistors

As one of the popular resistor types, metal film resistors are similar in construction to carbon film resistors, with the main difference being the use of a metal alloy as the resistive material rather than carbon. Metal film resistors are low noise, and stable with little resistance change due to temperature and applied voltage.

  • Carbon Composition Resistors

Carbon composition resistors use a solid block of material made from carbon powder, an insulating ceramic, and a binder material. The resistance is controlled by varying the ratio of carbon to the filler materials. The carbon composition in the resistor is affected by environmental conditions, especially humidity, and tends to change in resistance over time. Carbon composition resistors have a poor resistance tolerance, however, they have a good frequency response making them an option for high-frequency applications.

  • Carbon Film Resistors

Carbon film resistors use a thin layer of carbon on top of an insulating rod which is cut to form a narrow, long resistive path. The capabilities of a carbon film resistor are better than a carbon composition resistor, with power ratings up to 5 watts and better stability. However, their frequency response is much worse due to the inductance and capacitance caused by the resistive path cut into the film.

  • Thin Film Resistors

Borrowing from semiconductor processes, thin-film resistors are made through a vacuum deposition process called sputtering where a thin layer of conductive material is deposited on an insulating substrate. This thin layer is then photo-etched to create a resistive pattern. By precisely controlling the amount of material deposited and the resistive pattern, tolerances as tight as 0.01% can be achieved with thin-film resistors. Thin-film resistors are limited to about 2.5 watts and lower voltages than other resistor types but are very stable resistors.

  • Thick Film Resistors

Thick Film Resistors are made in a screen printing process using a conductive ceramic and glass mixture composite suspended in a liquid. Once the resistor has been screen printed, it is baked at high temperatures to remove the liquid and fuse the ceramic and glass composite. They have a high-temperature coefficient, with a 100°C temperature change resulting in up to a 2.5% change in resistance.


VIII The function of resistor

resistor

If the resistance of a resistor is close to zero ohms (for example, a large cross-section conductor between two points), the resistor has no impediment to the current. The circuit of the parallel resistor is short-circuited, and the current is infinite. If a resistor has infinite or large resistance, the loop of the resistor can be regarded as an open circuit and the current is zero.

 

The resistor commonly used in industry is between two extreme cases. It has a certain resistance. It can pass a certain current, but the current is not as large as that when it is short-circuited. The current limiting effect of a resistor is similar to the effect of a small diameter tube connected to two large-diameter tubes to limit the flow of water.

 

Resistance, the English name resistance, usually abbreviated to R, is a basic character of a conductor, which is related to the size, material and temperature of the conductor. Ohm's law says, I=U/R, then R=U/I, the basic unit of resistance is Ohm. With the Greek letter "Ω", there is such a definition: when a volt voltage is added to the conductor, a resistance value corresponding to an ampere current is generated. The main function of the resistance is to impede the flow of the current.

 

In fact, the resistance is natural, and the resistance usually referred to in the electronic product refers to a resistor such as a resistor. Ohm is often referred to as Europe. The commonly used units to represent resistance values are thousands of Europe (kΩ), mega (MΩ), and m Ω.

 


IX FAQ

1. How do you read resistor color codes?

Hold the resistor with these grouped bands to your left. Always read resistors from left to right. - Resistors never start with a metallic band on the left. If you have a resistor with a gold or silver band on one end, you have a 5% or 10% tolerance resistor.

 

2. What is the resistor color code?

Resistor Color Coding uses colored bands to quickly identify a resistor's resistive value and its percentage of tolerance with the physical size of the resistor indicating its wattage rating. ... The colors brown, red, green, blue, and violet are used as tolerance codes on 5-band resistors only.

 

3. How do you interpret the four Colour bands?

Most resistors have four stripes of color. The first three stripes indicate the resistance value, and the fourth stripe indicates the tolerance. Some resistors have five stripes of color, with four representing the resistance value and the last one the tolerance.

 

4. What is the color code?

A color code or color code is a system for displaying information by using different colors. The earliest examples of color codes in use are for long-distance communication by use of flags, as in semaphore communication. ... On forms and signage, the use of color can distract from black and white text.

 

5. How do you identify a resistor's color?

The colors on the first 2 or 3 bands correspond to numbers from 0 to 9, which represent the significant digits of the resistor's ohmic value. The last band gives the multiplier. For example, a resistor with brown, green and green bands is rated at 15 mega-ohms (15,000,000 ohms).

 

6. What are the colors on a resistor?

The four-band color code is the most common variation. These resistors have two bands for the resistance value, one multiplier and one tolerance band. In the example on the left, these bands are green, blue, red and gold. By using the color code chart, one finds that green stands for 5 and blue for 6.

 

7. How do you read a resistor color code 5?

If the colors on a 5 band resistor are in this order: brown, green, red, blue and violet. The values of color bands will be like this: Brown = 1, Green = 5, Red = 2, blue = 106, Violet = 0.10%.

 

8. What is a 47K resistor?

47 multiplied with 1000 is 47000. So this is a resistor with 47000 Ohms (47k Ohms). Tolerance of 5% means that the real value could be 5% higher or lower than 47k.

 

9. What does a 10K resistor look like?

A 10k ohm resistor has 4 color bands: brown, black, orange, and gold for 5% tolerance, respectively. A 1k ohm resistor has 4 color bands: brown, black, red, and gold for 5% tolerance, respectively.

 

10. What is resistor 1k ohm?

A resistor reduces (or resists) the flow of current. ... So, a 1k Ω resistor has a value of 1,000 ohms and the number we will code is 1,000.

 


Book Recommendation

  • Encyclopedia of Electronic Components Volume 1: Resistors, Capacitors, Inductors, Switches, Encoders, Relays, Transistors

Want to know how to use an electronic component? This first book of a three-volume set includes key information on electronics parts for your projects—complete with photographs, schematics, and diagrams. You’ll learn what each one does, how it works, why it’s useful, and what variants exist. No matter how much you know about electronics, you’ll find fascinating details you’ve never come across before. Perfect for teachers, hobbyists, engineers, and students of all ages, this reference puts reliable, fact-checked information right at your fingertips—whether you’re refreshing your memory or exploring a component for the first time. Beginners will quickly grasp important concepts, and more experienced users will find the specific details their projects require.

--Charles Platt(Author)

  • Resistor Theory and Technology

Provides engineers, scientists, technicians, and business people in the electronics industries a much-needed roadmap to understanding resistor design, fabrication, and use. The authors give an overview first, showing how design arises from scientific theories of resistive properties.

--Felix Zandman  (Author), Paul-Rene Simon (Author), and Joseph Szwarc (Author)

  • Resistors

A Cyprus Airways flight attendant resists the Turkish occupation of her country by participating in covert raids against their installations. When she helps a Greek-American security consultant resolve a skyjacking aboard one of her flights, they launch a passionate relationship complicated both by vengeful Palestinians and the consultant’s prior romantic involvement. Abduction, rescue at sea, forced separation and murder interrupt the love affair, but not the quest of the terrorists for retribution. The action in Resistors moves between the U.S. and the Eastern Mediterranean, integrating scenarios that haunt America’s consciousness: small town America and big-city hotels; skyjackings and vengeance-seeking Palestinian terrorists; Vietnam and Hinckley’s attempted assassination of Reagan. Each player in this international intrigue is flawed, but strong. All refuse to be victims.

--Peter T Tomaras  (Author), Alexander Tomaras (Cover Design), Jennifer Davis (Cover Design)

Relevant information about "What is Resistor and how to Read Resistor Color Code"

About the article "What is Resistor and how to Read Resistor Color Code", If you have better ideas, don't hesitate to  write your thoughts in the following comment area. You also can find more articles about electronic semiconductor through Google search engine, or refer to the following related articles.

Best Sales of diode

Photo Part Company Description Pricing (USD)
A6214KLKTR-T A6214KLKTR-T Company:Allegro MicroSystems Remark:IC LED DRVR REG PWM 2A 10SOIC Price:
3000+: $0.83200
Inquiry
AS6C1008-55TINL AS6C1008-55TINL Company:Alliance Memory, Inc. Remark:SRAM - Asynchronous Memory IC 1Mb (128K x 8) Parallel 32-TSOP I Price:
156+: $2.34301
Inquiry
AM29F016B-150EC AM29F016B-150EC Company:AMD Remark:Flash, 2MX8, 150ns, PDSO48, MO-142DD, TSOP-48 Price:
Call
Inquiry
AM29LV160DT-120EC AM29LV160DT-120EC Company:AMD Remark:1MX16 FLASH 3V PROM, 120ns, PDSO48, MO-142DD, TSOP-48 Price:
Call
Inquiry
MS27468E13B4P Company:Amphenol Aerospace Operations Remark:CONN RCPT MALE 4POS GOLD CRIMP Price:
1+: $76.58000
5+: $68.30400
10+: $56.83500
25+: $54.08280
Inquiry
ADSP-2185BSTZ-133 ADSP-2185BSTZ-133 Company:Analog Devices Inc. Remark:IC DSP CONTROLLER 16BIT 100TQFP Price:
1+: $59.37000
10+: $55.76900
25+: $53.97000
Inquiry

Alternative Models

Part Compare Manufacturers Category Description
Mfr.Part#:M29W128GL70N6E Compare: M29W128GH70N6E VS M29W128GL70N6E Manufacturers:Micron Category:Flash Memory Description: NOR Flash Parallel 3V/3.3V 128Mbit 16M/8M x 8Bit/16Bit 70ns 56Pin TSOP Tray
Mfr.Part#:M29W128GL70N6F Compare: M29W128GH70N6E VS M29W128GL70N6F Manufacturers:Micron Category:Flash Memory Description: NOR Flash Parallel 3V/3.3V 128Mbit 16M/8M x 8Bit/16Bit 70ns 56Pin TSOP T/R
Mfr.Part#:M29W128GH70N6F Compare: M29W128GH70N6E VS M29W128GH70N6F Manufacturers:Micron Category:Flash Memory Description: NOR Flash Parallel 3V/3.3V 128Mbit 16M/8M x 8Bit/16Bit 70ns 56Pin TSOP T/R
Mfr.Part#:M29W128GH70N6E Compare: Current Part Manufacturers:Micron Category:Memory Chip Description: NOR Flash Parallel 3V/3.3V 128Mbit 16M/8M x 8Bit/16Bit 70ns 56Pin TSOP Tray

Ordering & Quality

Image Mfr. Part # Company Description Package PDF Qty Pricing (USD)
ADSP-BF533SKSTZ-5V ADSP-BF533SKSTZ-5V Company:Analog Devices Inc. Remark:IC CCD SIGNAL PROCESSOR 176LQFP Package:QFP
DataSheet
In Stock:1
Inquiry
Price:
1+: $30.11000
Inquiry
ADSP-BF561SKBZ600 ADSP-BF561SKBZ600 Company:Analog Devices Inc. Remark:IC DSP 32BIT 600MHZ 297BGA Package:297-BGA
DataSheet
In Stock:26
Inquiry
Price:
1+: $49.62000
10+: $466.09000
25+: $1127.63000
100+: $4360.15000
Inquiry
AD7327BRUZ AD7327BRUZ Company:Analog Devices Inc. Remark:IC ADC 12BIT SAR 20TSSOP Package:20-TSSOP (0.173", 4.40mm Width)
DataSheet
In Stock:1545
Inquiry
Price:
1+: $10.02000
10+: $9.05200
25+: $8.63040
100+: $7.15700
250+: $6.52552
500+: $6.10450
Inquiry
AD7709ARUZ-REEL7 AD7709ARUZ-REEL7 Company:Analog Devices Inc. Remark:IC ADC 16BIT SIGMA-DELTA 24TSSOP Package:24-TSSOP (0.173", 4.40mm Width)
DataSheet
In Stock:1000
Inquiry
Price:
1000+: $6.01750
Inquiry
AD8062ARZ-R7 AD8062ARZ-R7 Company:Analog Devices Inc. Remark:IC OPAMP VFB 2 CIRCUIT 8SOIC Package:8-SOIC (0.154", 3.90mm Width)
DataSheet
In Stock:On Order
Inquiry
Price:
1000+: $2.39250
Inquiry
AD8131ARZ-REEL AD8131ARZ-REEL Company:Analog Devices Inc. Remark:IC OPAMP DIFF 1 CIRCUIT 8SOIC Package:8-SOIC (0.154", 3.90mm Width)
DataSheet
In Stock:2500
Inquiry
Price:
2500+: $2.71150
Inquiry
AD8280WASTZ AD8280WASTZ Company:Analog Devices Inc. Remark:IC LI-ION BATT MON 48LQFP Package:48-LQFP
DataSheet
In Stock:113
Inquiry
Price:
1+: $8.12000
10+: $7.33200
25+: $6.99040
100+: $5.79700
250+: $5.28552
500+: $4.94450
Inquiry
AD976ABRZ AD976ABRZ Company:Analog Devices Inc. Remark:IC ADC 16BIT SAR 28SOIC Package:28-SOIC (0.295", 7.50mm Width)
DataSheet
In Stock:114
Inquiry
Price:
1+: $67.20000
10+: $63.84000
25+: $62.16000
Inquiry

Related Articles

pinglun 8 comments

    • pingluntus
    • ALyne on 2018/3/23 11:32:48

    Excellent! This page about resistor is more comprehensive that wiki's resistor introduction !

      • pingluntu
      • author on 2018/3/23 11:42:08
        author

      Re:

      I am so happy to hear you admiration.Thank you!

    • pingluntus
    • Kit on 2018/3/23 11:39:38

    Hello~sir Is there an algorithm to find out all possible resistance values of series? parallel? and series-parallel arrangements given nn identical resistors, RR? All of them must be used. Thanks !

      • pingluntu
      • author on 2018/3/23 11:47:26
        author

      Re:

      Hi~Do you mean n identical resistors? Ok, let me assume that I have them,and the number of different series, parallel, and series-parallel combinations is given by the number of partitions n. The number of partitions of n is given by the sequence A000041(a(n) = number of partitions of n (the partition numbers) in OEIS.We can interpret each partition of n as a distinct way of arranging the nn resistors in series, parallel, or series-parallel. 

    • pingluntus
    • kit on 2018/3/23 11:48:36

    Sorry,sir,I am confusing still.Could you explain it more clearly?

      • pingluntu
      • author on 2018/3/23 13:49:10
        author

      Re:

      Let me take an example.When n=6n=6 we have 11 distinct partitions:

      1,1,1,1,1,1⇒6 resistors in series⇒resistance=6R

      2,1,1,1,1⇒2 resistors in parallel,4 resistors in series⇒resistance=412R

      2,2,1,1⇒2 resistors in parallel,2 resistors in parallel,2 resistors in series⇒resistance=3R

      2,2,2⇒2 resistors in parallel,2 resistors in parallel,2 resistors in parallel⇒resistance=112R

      3,1,1,1⇒3 resistors in parallel,3 resistors in series⇒resistance=313R

      3,2,1⇒3 resistors in parallel,2 resistors in parallel,1 resistors in series⇒resistance=156R

      3,3⇒3 resistors in parallel,3 in parallel⇒resistance=23R

      4,1,1⇒4 resistors in parallel,2 resistors in series⇒resistance=214R

      4,2⇒4 resistors in parallel,2 resistors in parallel⇒resistance=34R

      5,1⇒5 resistors in parallel,1 resistors in series⇒resistance=115R

      6⇒6 resistors in parallel⇒resistance=16R

      Actually, determining the resistances is simply the sum of the reciprocals of each partition. But this still requires being able to write out the partition rather than just counting the partitions. So if n1,n2,…,nkn1,n2,…,nk are integers such that n1+n2+⋯+nk=nn1+n2+⋯+nk=n then the total resistance given by this partition is

      (1n1+1n2+⋯+1nk)R.

    • pingluntus
    • curious on 2018/3/23 11:57:06

    After reading this article, I was so curious about the history of the resistance color code~

      • pingluntu
      • author on 2018/3/23 12:00:32
        author

      Re:

      The color code was developed in the 1920's by the Radio Manufacturers Association (RMA) as a three band code for resistor values. The three bands were more compact than the number value because the third band represented the number of zeroes. For example, 250 000 Ω was reduced to three bands. In addition, color bands remained visible in whatever position a resistor was soldered, whereas a stamped number value could be out of sight. The fourth band, representing the tolerance, was added later.Initially the three colors were not three separate bands, and there was no neutral background color. Instead, they were the body color, the tip color and the dot color, as in the diagram. Identical adjacent colors were allowed. Want to know more history about resistor color code,you can google it.


    • pingluntus
    • curious on 2018/3/23 12:00:44

    After reading this article, I was so curious about the history of the resistance code color~

    • pingluntus
    • Kit on 2018/3/23 12:02:08

    @sir Thanks very much. But I guess the mathematical term for it is partition? Do you think there is a closed-form solution to get all the coefficients of RR?

      • pingluntu
      • author on 2018/3/23 12:05:48
        author

      Re:

      No there is not a closed form for determining the number of partitions, but there is a generating function that produces the numbers. If you need the various resistances, I'm not sure there is a good way of going about it right now. If you just need to know how many distinct resistances there are, this will do the trick. Well,I need to emphasize that I am not assure my question is right completedly.Maybe you can ask more professional electronic perpon. Good luck to you.

    • pingluntus
    • mike on 2018/3/23 12:06:43

    Interesting comments~

    • pingluntus
    • niki on 2018/4/9 15:49:39

    Article is rich and the comments are interesting~hah~

Leave a Reply

Your email address will not be published.

 
 
   
 
code image
Rating: poor fair good very good excellent

# 0 1 2 3 4 5 6 7 8 9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z