• Become a seller
  • Vendors
  • Our blog
  • Gift certificates
  • Bestsellers
  • Newest products
  • Sale
hallroad
My Products 0 item(s) - Rs. 0
0

Cart is empty

View cart
Checkout
  • All Categories
    • Camera & Photo
      Camera & Photo

      Binoculars & Telescopes

      Camcorders

      Camera & Photo Accessories

      Camera Drones

      Camera Lenses Filters

      Digital Cameras

      Digital Photo Frames

      Film Photography

      Flashes & Flash Accessories

      Photo Lighting and Studio Equipment

      Replacement Parts & Tools

      Tripods & Supports

    • Commercial & Industrial
      Commercial & Industrial

      3D_printers

      Batteries & UPS

      Cable TV

      CNC & Laser Cutters

      Electric Panels & Cabinets

      Generators/GenSets

      Industrial Robotics

      Industrial Displays

      Industrial Sensors & Actuators

      Industrial Tools

      Inverters/VFDs

      Measurement & Analysis Instruments

    • Computer & Office
      Computer & Office

      Cables & Connectors

      Computer Cleaners

      Computer Components & Parts

      Computer Peripherals

      Demo Board & Accessories

      Desktops & Servers

      DIY Gaming PC

      Drives, Storage & Blank Media

      Gaming Laptops

      Industrial Computer & Accessories

      Laptop & Desktop Accessories

      Laptops & Netbooks

    • Home Appliances
      Home Appliances

      Bathroom Fixtures

      Building Supplies

      Commercial Appliances

      Electrical Equipment & Supplies

      Hardware

      Home Appliance Parts

      Household Appliances

      Kitchen Appliances & Fixtures

      Major Appliances

      Painting Supplies & Wall Treatments

      Personal Care Appliances

      Plumbing

    • Lights & Lighting
      Lights & Lighting

      Book Lights

      Ceiling Lights & Fans

      Commercial Lighting

      Holiday Lighting

      Lamps & Shades

      LED Lamps

      LED Lighting

      Light Bulbs

      Lighting Accessories

      Night Lights

      Novelty Lighting

      Outdoor Lighting

    • Mobile & Communication
      Mobile & Communication

      Cables & Adapters

      Chargers & Cradles

      Communication Equipment

      Headsets, Hands-free

      Mobile Phone Accessories

      Mobile Phone Batteries

      Mobile Phone Parts

      Mobile Phones

      Phone Bags, Cases, Covers, & Skins

      Power Bank

      Screen protectors

      Smart Watches

    • Tools
      Tools

      Abrasive Tools

      Abrasives

      Construction Tools

      Garden Tools

      Hand & Power Tool Accessories

      Hand Tools

      Lifting Tools & Accessories

      Machine Tools & Accessories

      Measurement & Analysis Instruments

      Power Tools

      Riveter Guns

      Tool Organizers

    • Consumer Electronics
      Consumer Electronics

      Accessories & Parts

      Calculators

      DVD & Blu-ray players

      Earphones & Headphones

      Electronic Cigarettes

      Consument Gadgets

      Home Audio & Video

      Home Automation

      Home Speakers & Subwoofers

      Home Surveillance

      Media Streamers

      Portable Audio & Video Players

    • Security & Protection
      Security & Protection

      Access Control

      Building Automation

      Door Intercom

      Emergency Kits

      Fire Protection

      Lightning Protection

      Metal Detectors

      Roadway Safety

      Safes

      Security Alarm

      Self Defense Supplies

      Smart Card System

    • Components
      Components

      Component Boards/Kits

      Development Boards/Kits & DIY

      Electronic Accessories & Supplies

      IC's & Electronic Components

      Instruments & Tools

      Robotic Kits

      Sensors & Sensor Modules

      Signs Boards & Displays

      Wholesale Lots (Electronic Components)

    • Services
      Services

      Cable TV Installations

      Electrician

      Electronic Repairs - Domestic & Commercial

      Electronic Repairs - Industrial

      Installation - Commercial

      Installation - Domestic

      Installation - Industrial

      Software Installation

      Software Development - General

      Software Development - Embedded

      Software Development - WebSites

My Products 0 item(s) - Rs. 0
0

Cart is empty

View cart
Checkout
  • All Categories
    • Camera & Photo
      Camera & Photo

      Binoculars & Telescopes

      Camcorders

      Camera & Photo Accessories

      Camera Drones

      Camera Lenses Filters

      Digital Cameras

      Digital Photo Frames

      Film Photography

      Flashes & Flash Accessories

      Photo Lighting and Studio Equipment

      Replacement Parts & Tools

      Tripods & Supports

    • Commercial & Industrial
      Commercial & Industrial

      3D_printers

      Batteries & UPS

      Cable TV

      CNC & Laser Cutters

      Electric Panels & Cabinets

      Generators/GenSets

      Industrial Robotics

      Industrial Displays

      Industrial Sensors & Actuators

      Industrial Tools

      Inverters/VFDs

      Measurement & Analysis Instruments

    • Computer & Office
      Computer & Office

      Cables & Connectors

      Computer Cleaners

      Computer Components & Parts

      Computer Peripherals

      Demo Board & Accessories

      Desktops & Servers

      DIY Gaming PC

      Drives, Storage & Blank Media

      Gaming Laptops

      Industrial Computer & Accessories

      Laptop & Desktop Accessories

      Laptops & Netbooks

    • Home Appliances
      Home Appliances

      Bathroom Fixtures

      Building Supplies

      Commercial Appliances

      Electrical Equipment & Supplies

      Hardware

      Home Appliance Parts

      Household Appliances

      Kitchen Appliances & Fixtures

      Major Appliances

      Painting Supplies & Wall Treatments

      Personal Care Appliances

      Plumbing

    • Lights & Lighting
      Lights & Lighting

      Book Lights

      Ceiling Lights & Fans

      Commercial Lighting

      Holiday Lighting

      Lamps & Shades

      LED Lamps

      LED Lighting

      Light Bulbs

      Lighting Accessories

      Night Lights

      Novelty Lighting

      Outdoor Lighting

    • Mobile & Communication
      Mobile & Communication

      Cables & Adapters

      Chargers & Cradles

      Communication Equipment

      Headsets, Hands-free

      Mobile Phone Accessories

      Mobile Phone Batteries

      Mobile Phone Parts

      Mobile Phones

      Phone Bags, Cases, Covers, & Skins

      Power Bank

      Screen protectors

      Smart Watches

    • Tools
      Tools

      Abrasive Tools

      Abrasives

      Construction Tools

      Garden Tools

      Hand & Power Tool Accessories

      Hand Tools

      Lifting Tools & Accessories

      Machine Tools & Accessories

      Measurement & Analysis Instruments

      Power Tools

      Riveter Guns

      Tool Organizers

    • Consumer Electronics
      Consumer Electronics

      Accessories & Parts

      Calculators

      DVD & Blu-ray players

      Earphones & Headphones

      Electronic Cigarettes

      Consument Gadgets

      Home Audio & Video

      Home Automation

      Home Speakers & Subwoofers

      Home Surveillance

      Media Streamers

      Portable Audio & Video Players

    • Security & Protection
      Security & Protection

      Access Control

      Building Automation

      Door Intercom

      Emergency Kits

      Fire Protection

      Lightning Protection

      Metal Detectors

      Roadway Safety

      Safes

      Security Alarm

      Self Defense Supplies

      Smart Card System

    • Components
      Components

      Component Boards/Kits

      Development Boards/Kits & DIY

      Electronic Accessories & Supplies

      IC's & Electronic Components

      Instruments & Tools

      Robotic Kits

      Sensors & Sensor Modules

      Signs Boards & Displays

      Wholesale Lots (Electronic Components)

    • Services
      Services

      Cable TV Installations

      Electrician

      Electronic Repairs - Domestic & Commercial

      Electronic Repairs - Industrial

      Installation - Commercial

      Installation - Domestic

      Installation - Industrial

      Software Installation

      Software Development - General

      Software Development - Embedded

      Software Development - WebSites

  • New Items
  • On Sale
  • Bestsellers
  • Shop by Vendor
  • Contact us
  • Our Blog
My account
  • Orders
  • Wish list
Track my order(s)
Sign inorRegister
Forgot your password?
Register for a new account
  • All Categories
    • Camera & Photo
      Camera & Photo

      Binoculars & Telescopes

      Camcorders

      Camera & Photo Accessories

      Camera Drones

      Camera Lenses Filters

      Digital Cameras

      Digital Photo Frames

      Film Photography

      Flashes & Flash Accessories

      Photo Lighting and Studio Equipment

      Replacement Parts & Tools

      Tripods & Supports

    • Commercial & Industrial
      Commercial & Industrial

      3D_printers

      Batteries & UPS

      Cable TV

      CNC & Laser Cutters

      Electric Panels & Cabinets

      Generators/GenSets

      Industrial Robotics

      Industrial Displays

      Industrial Sensors & Actuators

      Industrial Tools

      Inverters/VFDs

      Measurement & Analysis Instruments

    • Computer & Office
      Computer & Office

      Cables & Connectors

      Computer Cleaners

      Computer Components & Parts

      Computer Peripherals

      Demo Board & Accessories

      Desktops & Servers

      DIY Gaming PC

      Drives, Storage & Blank Media

      Gaming Laptops

      Industrial Computer & Accessories

      Laptop & Desktop Accessories

      Laptops & Netbooks

    • Home Appliances
      Home Appliances

      Bathroom Fixtures

      Building Supplies

      Commercial Appliances

      Electrical Equipment & Supplies

      Hardware

      Home Appliance Parts

      Household Appliances

      Kitchen Appliances & Fixtures

      Major Appliances

      Painting Supplies & Wall Treatments

      Personal Care Appliances

      Plumbing

    • Lights & Lighting
      Lights & Lighting

      Book Lights

      Ceiling Lights & Fans

      Commercial Lighting

      Holiday Lighting

      Lamps & Shades

      LED Lamps

      LED Lighting

      Light Bulbs

      Lighting Accessories

      Night Lights

      Novelty Lighting

      Outdoor Lighting

    • Mobile & Communication
      Mobile & Communication

      Cables & Adapters

      Chargers & Cradles

      Communication Equipment

      Headsets, Hands-free

      Mobile Phone Accessories

      Mobile Phone Batteries

      Mobile Phone Parts

      Mobile Phones

      Phone Bags, Cases, Covers, & Skins

      Power Bank

      Screen protectors

      Smart Watches

    • Tools
      Tools

      Abrasive Tools

      Abrasives

      Construction Tools

      Garden Tools

      Hand & Power Tool Accessories

      Hand Tools

      Lifting Tools & Accessories

      Machine Tools & Accessories

      Measurement & Analysis Instruments

      Power Tools

      Riveter Guns

      Tool Organizers

    • Consumer Electronics
      Consumer Electronics

      Accessories & Parts

      Calculators

      DVD & Blu-ray players

      Earphones & Headphones

      Electronic Cigarettes

      Consument Gadgets

      Home Audio & Video

      Home Automation

      Home Speakers & Subwoofers

      Home Surveillance

      Media Streamers

      Portable Audio & Video Players

    • Security & Protection
      Security & Protection

      Access Control

      Building Automation

      Door Intercom

      Emergency Kits

      Fire Protection

      Lightning Protection

      Metal Detectors

      Roadway Safety

      Safes

      Security Alarm

      Self Defense Supplies

      Smart Card System

    • Components
      Components

      Component Boards/Kits

      Development Boards/Kits & DIY

      Electronic Accessories & Supplies

      IC's & Electronic Components

      Instruments & Tools

      Robotic Kits

      Sensors & Sensor Modules

      Signs Boards & Displays

      Wholesale Lots (Electronic Components)

    • Services
      Services

      Cable TV Installations

      Electrician

      Electronic Repairs - Domestic & Commercial

      Electronic Repairs - Industrial

      Installation - Commercial

      Installation - Domestic

      Installation - Industrial

      Software Installation

      Software Development - General

      Software Development - Embedded

      Software Development - WebSites

hallroad
My Products 0 item(s) - Rs. 0
0

Cart is empty

View cart
Checkout
My account
  • Orders
  • Wish list
Track my order(s)
Sign inorRegister
Forgot your password?
Register for a new account
HomeComponentsIC's & Electronic Components2 Watt 5% Resistor
5 of 10

2 Watt 5% Resistor

Digilog Electronics Contact vendor
On backorder
2242
2 Watt 5% Resistor

Rs. 0

Write a review
Take a Stance, The Resist Stance Resistors – the most ubiquitous of electronic components. They are a critical piece in just about every circuit. And they play a major role in our favorite equation, Ohm’s Law . In this, our pièce de résistance , we’ll cover: What is a...

Minimum quantity for "2 Watt 5% Resistor" is 10.

− +
Add to Wishlist
  • Tweet
  • Pinterest
  • Share

Please sign in to contact the vendor

Forgot your password?
Register for a new account
  • Description
  • Tags
  • Reviews

Take a Stance, The Resist Stance

Resistors – the most ubiquitous of electronic components. They are a critical piece in just about every circuit. And they play a major role in our favorite equation, Ohm’s Law.

resistors

In this, our pièce de résistance, we’ll cover:

  • What is a resistor?!
  • Resistor units
  • Resistor circuit symbol(s)
  • Resistors in series and parallel
  • Different variations of resistors
  • Color coding decoding
  • Surface mount resistor decoding
  • Example resistor applications

Consider reading…

Some of the concepts in this tutorial build on previous electronics knowledge. Before jumping into this tutorial, consider reading (at least skimming) these first:

  • What is Electricity?
  • Voltage, Current, Resistance, and Ohm’s Law
  • What is a Circuit
  • Series vs. Parallel Circuits
  • How to Use A Multimeter – Specifically check out the measuring resistance section.
  • Metric Prefixes

Resistor Basics

Resistors are electronic components which have a specific, never-changing electrical resistance. The resistor’s resistance limits the flow of electrons through a circuit.

They are passive components, meaning they only consume power (and can’t generate it). Resistors are usually added to circuits where they complement active components like op-amps, microcontrollers, and other integrated circuits. Commonly resistors are used to limit current, divide voltages, and pull-up I/O lines.

Resistor units

The electrical resistance of a resistor is measured in ohms. The symbol for an ohm is the greek capital-omega: Ω. The (somewhat roundabout) definition of 1Ω is the resistance between two points where 1 volt (1V) of applied potential energy will push 1 ampere (1A) of current.

As SI units go, larger or smaller values of ohms can be matched with a prefix like kilo-, mega-, or giga-, to make large values easier to read. It’s very common to see resistors in the kilohm (kΩ) and megaohm (MΩ) range (much less common to see miliohm (mΩ) resistors). For example, a 4,700Ω resistor is equivalent to a 4.7kΩ resistor, and a 5,600,000Ω resistor can be written as 5,600kΩ or (more commonly as) 5.6MΩ.

Schematic symbol

All resistors have two terminals, one connection on each end of the resistor. When modeled on a schematic, a resistor will show up as one of these two symbols:

Resistor schematic symbols

Two common resistor schematic symbols. R1 is an American-style 1kΩ resistor, and R2 is an international-style 47kΩ resistor.

The terminals of the resistor are each of the lines extending from the squiggle (or rectangle). Those are what connect to the rest of the circuit.

The resistor circuit symbols are usually enhanced with both a resistance value and a name. The value, displayed in ohms, is obviously critical for both evaluating and actually constructing the circuit. The name of the resistor is usually an R preceding a number. Each resistor in a circuit should have a unique name/number. For example, here’s a few resistors in action on a 555 timer circuit:

Example schematic with resistors - a 555 timer

In this circuit, resistors play a key role in setting the frequency of the 555 timer’s output. Another resistor (R3) limits the current through an LED.


Types of Resistors

Resistors come in a variety of shapes and sizes. They might be through-hole or surface-mount. They might be a standard, static resistor, a pack of resistors, or a special variable resistor.

Termination and mounting

Resistors will come in one of two termination-types: through-hole or surface-mount. These types of resistors are usually abbreviated as either PTH (plated through-hole) or SMD/SMT (surface-mount technology or device).

Through-hole resistors come with long, pliable leads which can be stuck into a breadboard or hand-soldered into a prototyping board or printed circuit board (PCB). These resistors are usually more useful in breadboarding, prototyping, or in any case where you’d rather not solder tiny, little 0.6mm-long SMD resistors. The long leads usually require trimming, and these resistors are bound to take up much more space than their surface-mount counterparts.

The most common through-hole resistors come in an axial package. The size of an axial resistor is relative to its power rating. A common ½W resistor measures about 9.2mm across, while a smaller ¼W resistor is about 6.3mm long.

1/4 and 1/2 watt resistors

A half-watt (½W) resistor (above) sized up to a quarter-watt (¼W).

Surface-mount resistors are usually tiny black rectangles, terminated on either side with even smaller, shiny, silver, conductive edges. These resistors are intended to sit on top of PCBs, where they’re soldered onto mating landing pads. Because these resistors are so small, they’re usually set into place by a robot, and sent through an oven where solder melts and holds them in place.

SMD resistor on a quarter

A tiny 0603 330Ω resistor hovering over shiny George Washington’s nose on top of a U.S. quarter.

SMD resistors come in standardized sizes; usually either 0805 (0.8mm long by 0.5mm wide), 0603, or 0402. They’re great for mass circuit-board-production, or in designs where space is a precious commodity. They take a steady, precise hand to manually solder, though!

Resistor composition

Resistors can be constructed out of a variety of materials. Most common, modern resistors are made out of either a carbon, metal, or metal-oxide film. In these resistors, a thin film of conductive (though still resistive) material is wrapped in a helix around and covered by an insulating material. Most of the standard, no-frills, through-hole resistors will come in a carbon-film or metal-film composition.

Peeled away view of carbon-film resistors

Peek inside the guts of a few carbon-film resistors. Resistance values from top to bottom: 27Ω, 330Ω and a 3.3MΩ. Inside the resistor, a carbon film is wrapped around an insulator. More wraps means a higher resistance. Pretty neat!

Other through-hole resistors might be wirewound or made of super-thin metallic foil. These resistors are usually more expensive, higher-end components specifically chosen for their unique characteristics like a higher power-rating, or maximum temperature range.

Surface-mount resistors are usually either thick or thin-film variety. Thick-film is usually cheaper but less precise than thin. In both resistor types, a small film of resistive metal alloy is sandwiched between a ceramic base and glass/epoxy coating, and then connected to the terminating conductive edges.

Special resistor packages

There are a variety of other, special-purpose resistors out there. Resistors may come in pre-wired packs of five-or-so resistor arrays. Resistors in these arrays may share a common pin, or be set up as voltage dividers.

Resistor Network

An array of five 330Ω resistors, all tied together at one end.

Resistors don’t have to be static either. Variable resistors, known as rheostats, are resistors which can be adjusted between a specific range of values. Similar to the rheostat is the potentiometer. Pots connect two resistors internally, in series, and adjust a center tap between them creating an adjustable voltage divider. These variable resistors are often used for inputs, like volume knobs, which need to be adjustable.

A smattering of potentiometers

A smattering of potentiometers. From top-left, clockwise: a standard 10k trimpot, 2-axis joystick, softpot, slide pot, classic right-angle, and a breadboard friendly 10k trimpot.


Decoding Resistor Markings

Though they may not display their value outright, most resistors are marked to show what their resistance is. PTH resistors use a color-coding system (which really adds some flair to circuits), and SMD resistors have their own value-marking system.

Decoding the color bands

Through-hole, axial resistors usually use the color-band system to display their value. Most of these resistors will have four bands of color circling the resistor.

Resistors showing their stripes

The first two bands indicate the two most-significant digits of the resistor’s value. The third band is a weight value, which multiplies the two significant digits by a power of ten.

The final band indicates the tolerance of the resistor. The tolerance explains how much more or less the actualresistance of the resistor can be compared to what its nominal value is. No resistor is made to perfection, and different manufacturing processes will result in better or worse tolerances. For example, a 1kΩ resistor with 5% tolerance could actually be anywhere between 0.95kΩ and 1.05kΩ.

How do you tell which band is first and last? The last, tolerance band is often clearly separated from the value bands, and usually it’ll either be silver or gold.

Here’s a table of each of the colors and which value, multiplier or tolerance they represent:

Color Digit value Multiplier Multiplied Out Tolerance
Black 0 100 1  
Brown 1 101 10  
Red 2 102 100  
Orange 3 103 1,000  
Yellow 4 104 10000  
Green 5 105 100,000  
Blue 6 106 1,000,000  
Violet 7 107 10,000,000  
Gray 8 108 100,000,000  
White 9 109 1,000,000,000  
Gold       ±5%
Silver       ±10%

Here’s an example of a 4.7kΩ resistor with four color bands:

Close-up of a 4.7kOhm resistor

When decoding the resistor color bands, consult a resistor color code table like the one above. For the first two bands, find that color’s corresponding digit value. The 4.7kΩ resistor has color bands of yellow and violet to begin – which have digit values of 4 and 7 (47). The third band of the 4.7kΩ is red, which indicates that the 47 should be multiplied by 102 (or 100). 47 times 100 is 4,700!

If you’re trying to commit the color band code to memory, a mnemonic device might help. There are a handful of(sometimes unsavory) mnemonics out there, to help remember the resistor color code. A good one, which spells out the difference between black and brown is:

“Big brown rabbits often yield great big vocal groans when gingerly snapped.”

Or, if you remember “ROY G. BIV”, subtract the indigo (poor indigo, no one remembers indigo), and add black and brown to the front and gray and white to the back of the classic rainbow color-order.

Color Code Calculator

If you’d rather skip the math (we won’t judge :), and just use a handy calculator, give this a try!

Band 1 Band 2 Band 3   Band 4
Value 1 (MSV) Value 2 Weight   Tolerance
Black (0)
Brown (1)
Red (2)
Orange (3)
Yellow (4)
Green (5)
Blue (6)
Violet (7)
Gray (8)
White (9)
Black (0)
Brown (1)
Red (2)
Orange (3)
Yellow (4)
Green (5)
Blue (6)
Violet (7)
Gray (8)
White (9)
Black (1)
Brown (10)
Red (100)
Orange (1k)
Yellow (10k)
Green (100k)
Blue (1M)
Violet (10M)
Gray (100M)
White (1G)
  Gold (± 5%)
Silver (± 10%)

Resistance:

1,000 Ω ±5%

Decoding surface-mount markings

SMD resistors, like those in 0603 or 0805 packages, have their own way of displaying their value. There are a few common marking methods you’ll see on these resistors. They’ll usually have three to four characters – numbers or letters – printed on top of the case.

If the three characters you’re seeing are all numbers, you’re probably looking at an E24 marked resistor. These markings actually share some similarity with the color-band system used on the PTH resistors. The first two numbers represent the first two most-significant digits of the value, the last number represents a magnitude.

Examples of E-24 marked SMD resistors

In the above example picture, resistors are marked 104, 105, 205, 751, and 754. The resistor marked with 104 should be 100kΩ (10×104), 105 would be 1MΩ (10×105), and 205 is 2MΩ (20×105). 751 is 750Ω (75×101), and 754 is 750kΩ (75×104).

Another common coding system is E96, and it’s the most cryptic of the bunch. E96 resistors will be marked with three characters – two numbers at the beginning and a letter at the end. The two numbers tell you the first three digits of the value, by corresponding to one of the not-so-obvious values on this lookup table.

Code Value   Code Value   Code Value   Code Value   Code Value   Code Value
01 100   17 147   33 215   49 316   65 464   81 681
02 102   18 150   34 221   50 324   66 475   82 698
03 105   19 154   35 226   51 332   67 487   83 715
04 107   20 158   36 232   52 340   68 499   84 732
05 110   21 162   37 237   53 348   69 511   85 750
06 113   22 165   38 243   54 357   70 523   86 768
07 115   23 169   39 249   55 365   71 536   87 787
08 118   24 174   40 255   56 374   72 549   88 806
09 121   25 178   41 261   57 383   73 562   89 825
10 124   26 182   42 267   58 392   74 576   90 845
11 127   27 187   43 274   59 402   75 590   91 866
12 130   28 191   44 280   60 412   76 604   92 887
13 133   29 196   45 287   61 422   77 619   93 909
14 137   30 200   46 294   62 432   78 634   94 931
15 140   31 205   47 301   63 442   79 649   95 953
16 143   32 210   48 309   64 453   80 665   96 976

The letter at the end represents a multiplier, matching up to something on this table:

Letter Multiplier   Letter Multiplier   Letter Multiplier
Z 0.001   A 1   D 1000
Y or R 0.01   B or H 10   E 10000
X or S 0.1   C 100   F 100000

Resistors marked with E-96 codes

So a 01C resistor is our good friend, 10kΩ (100×100), 01B is 1kΩ (100×10), and 01D is 100kΩ. Those are easy, other codes may not be. 85A from the picture above is 750Ω (750×1) and 30C is actually 20kΩ.


Power Rating

The power rating of a resistor is one of the more hidden values. Nevertheless it can be important, and it’s a topic that’ll come up when selecting a resistor type.

Power is the rate at which energy is transformed into something else. It’s calculated by multiplying the voltage difference across two points by the current running between them, and is measured in units of a watt (W). Light bulbs, for example, power electricity into light. But a resistor can only turn electrical energy running through it into heat. Heat isn’t usually a nice playmate with electronics; too much heat leads to smoke, sparks, and fire!

Every resistor has a specific maximum power rating. In order to keep the resistor from heating up too much, it’s important to make sure the power across a resistor is kept under it’s maximum rating. The power rating of a resistor is measured in watts, and it’s usually somewhere between ⅛W (0.125W) and 1W. Resistors with power ratings of more than 1W are usually referred to as power resistors, and are used specifically for their power dissipating abilities.

Finding a resistor’s power rating

A resistor’s power rating can usually be deduced by observing its package size. Standard through-hole resistors usually come with ¼W or ½W ratings. More special purpose, power resistors might actually list their power rating on the resistor.

Some examples of power resistors

These power resistors can handle a lot more power before they blow. From top-right to bottom-left there are examples of 25W, 5W and 3W resistors, with values of 2Ω, 3Ω 0.1Ω and 22kΩ. Smaller power-resistors are often used to sense current.

The power ratings of surface mount resistors can usually be judged by their size as well. Both 0402 and 0603-size resistors are usually rated for 1/16W, and 0805’s can take 1/10W.

Measuring power across a resistor

Power is usually calculated by multiplying voltage and current (P = IV). But, by applying Ohm’s law, we can also use the resistance value in calculating power. If we know the current running through a resistor, we can calculate the power as:

P=I^2*R

Or, if we know the voltage across a resistor, the power can be calculated as:

  • 1M Ohm Volum Resistor
  • 2 watt resistor
  • resistance
  • resistor

No posts found

Write a review

Similar products

-15%
1000Pcs 1/4 WATT 5% RESISTOR
1000Pcs 1/4 WATT 5% RESISTOR
Rs. 110
Rs. 130
1M Ohm Volum Resistor
1M Ohm Volum Resistor
Rs. 18
22 Ohm 5W
22 Ohm 5W
Rs. 15
3.3 Ohm 5W
3.3 Ohm 5W
Rs. 15
1W Single Turn Rotary Taper Carbon Wire wound Potentiometer Volum Resistor
1W Single Turn Rotary Taper Carbon Wire wound Potentiometer Volum Resistor
Rs. 85
3386 Single Turn Variable Resistor Potentiometer Trimmer Resistor 3386 Single Turn Variable Resistor Potentiometer Trimmer Resistor
3386 Single Turn Variable Resistor Potentiometer Trimmer Resistor
Rs. 10
Volume Type Variable Resistor Potentiometer Trimmer Resistor Rheostate
Volume Type Variable Resistor Potentiometer Trimmer Resistor Rheostate
Rs. 20
-50%
1/4 Watt 5% Resistor 0.25W Resistor
1/4 Watt 5% Resistor 0.25W Resistor
Rs. 1
Rs. 2
Force Sensitive Resistor FSR Force Sensitive Resistor FSR
Force Sensitive Resistor FSR
Rs. 500
Force Sensitive Resistor FSR Square Force Sensitive Resistor FSR Square
Force Sensitive Resistor FSR Square
Rs. 900
1 Watt 5% Resistor 0.25W Resistor
1 Watt 5% Resistor 0.25W Resistor
Rs. 0
Variable Resistor RM065 Variable Resistor RM065 Variable Resistor RM065
Variable Resistor RM065
Contact us for a price
Resistor HYB-16B Resistor HYB-16B
Resistor HYB-16B
Rs. 500
1M Ohm Resistor 1 Mega Ohm Resistor 1/4 Watt 5% Resistor 0.25W Resistor
1M Ohm Resistor 1 Mega Ohm Resistor 1/4 Watt 5% Resistor 0.25W Resistor
Rs. 1
22 Ohm 10 Watt Resistor
22 Ohm 10 Watt Resistor
Rs. 30
10Mohm 1/4 Watt 5% Resistor 0.25W Resistor
10Mohm 1/4 Watt 5% Resistor 0.25W Resistor
Rs. 5

GET OUR LATEST NEWS & UPDATES:

Become a seller

  • Apply for a seller account
  • Vendor terms & conditions

Extras

  • About us
  • Contact us
  • Gift certificates
  • Vendor List
  • Sitemap
  • Blog

Customer Service

  • Free Shipping
  • Warranty
  • Returns
  • Privacy Policy
  • FAQ

Contact us

Digilog Electronics,

UG21 1st Floor Qazi Electronics Center ,

Opposite State Bank Near Milli Shoes Mall Road

Lahore Pakistan.

04237325296, 03124002221
Email: hallroad.org@gmail.com

Powered By Digilog Electronics