24 Ohm 6 Watt Resistor

Passive electrical component providing electrical resistance

Resistor

An array of axial-lead resistors
Type	Passive
Working principle‍	Electric resistance
Electronic symbol
IEEE schematic symbols

Various resistor types of different shapes and sizes

A resistor is a passive 2-last electrical component that implements electrical resistance every bit a circuit element. In electronic circuits, resistors are used to reduce current menstruation, adjust point levels, to dissever voltages, bias active elements, and terminate manual lines, among other uses. Loftier-power resistors that can dissipate many watts of electrical power as heat may be used equally function of motor controls, in power distribution systems, or as test loads for generators. Stock-still resistors have resistances that only change slightly with temperature, fourth dimension or operating voltage. Variable resistors can be used to adjust excursion elements (such as a book control or a lamp dimmer), or as sensing devices for heat, light, humidity, force, or chemical activity.

Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Applied resistors as discrete components tin exist composed of various compounds and forms. Resistors are as well implemented within integrated circuits.

The electrical part of a resistor is specified by its resistance: common commercial resistors are manufactured over a range of more than than 9 orders of magnitude. The nominal value of the resistance falls within the manufacturing tolerance, indicated on the component.

Electronic symbols and notation

2 typical schematic diagram symbols are every bit follows:

• 

  ANSI-style: (a) resistor, (b) rheostat (variable resistor), and (c) potentiometer

• 

  IEC resistor symbol

The notation to country a resistor'south value in a circuit diagram varies.

One common scheme is the RKM code following IEC 60062. Rather than using a decimal separator, this notation uses a letter loosely associated with SI prefixes corresponding with the part's resistance. For instance, 8K2 as part marker code, in a circuit diagram or in a pecker of materials (BOM) indicates a resistor value of 8.2 kΩ. Boosted zeros imply a tighter tolerance, for example 15M0 for iii significant digits. When the value tin be expressed without the need for a prefix (that is, multiplicator 1), an "R" is used instead of the decimal separator. For example, 1R2 indicates ane.ii Ω, and 18R indicates 18 Ω.

Theory of performance

The hydraulic analogy compares electric current flowing through circuits to water flowing through pipes. When a pipe (left) is clogged with pilus (correct), it takes a larger pressure to accomplish the same catamenia of water. Pushing electric current through a large resistance is like pushing h2o through a pipe clogged with hair: It requires a larger push (voltage) to drive the same flow (current).^[i]

Ohm's law

The behaviour of an ideal resistor is described past Ohm'southward law:

$${\displaystyle V=I\cdot R.}$$

Ohm's law states that the voltage ( ${\displaystyle V}$ ) across a resistor is proportional to the current ( ${\displaystyle I}$ ) passing through information technology, where the abiding of proportionality is the resistance ( ${\displaystyle R}$ ). For example, if a 300-ohm resistor is attached across the terminals of a 12-volt battery, then a current of 12 / 300 = 0.04 amperes flows through that resistor.

The ohm (symbol: Ω) is the SI unit of measurement of electrical resistance, named afterwards Georg Simon Ohm. An ohm is equivalent to a volt per ampere. Since resistors are specified and manufactured over a very large range of values, the derived units of milliohm (one mΩ = 10⁻³ Ω), kilohm (1 kΩ = 10³ Ω), and megohm (1 MΩ = 10^vi Ω) are too in common usage.^{[two] [3] : p.xx}

Series and parallel resistors

The total resistance of resistors connected in series is the sum of their private resistance values.

$${\displaystyle R_{\mathrm {eq} }=R_{i}+R_{2}+\cdots +R_{due north}.}$$

The total resistance of resistors connected in parallel is the reciprocal of the sum of the reciprocals of the private resistors.^{[3] : p.20ff}

$${\displaystyle {\frac {one}{R_{\mathrm {eq} }}}={\frac {1}{R_{1}}}+{\frac {1}{R_{2}}}+\cdots +{\frac {1}{R_{northward}}}.}$$

For example, a x ohm resistor connected in parallel with a 5 ohm resistor and a 15 ohm resistor produces one / 1/ten + ane/5 + 1/15 ohms of resistance, or thirty / 11 = 2.727 ohms.

A resistor network that is a combination of parallel and serial connections tin can exist cleaved upwards into smaller parts that are either one or the other. Some circuitous networks of resistors cannot be resolved in this mode, requiring more sophisticated circuit analysis. Generally, the Y-Δ transform, or matrix methods can exist used to solve such problems.^{[4] [five] [half dozen]}

Power dissipation

At any instant, the ability P (watts) consumed by a resistor of resistance R (ohms) is calculated as:

$${\displaystyle P=Iv=I^{ii}R={\frac {5^{2}}{R}}}$$

where V (volts) is the voltage beyond the resistor and I (amps) is the electric current flowing through it. Using Ohm'due south law, the two other forms can exist derived. This power is converted into heat which must be prodigal by the resistor's package before its temperature rises excessively.^{[3] : p.22}

Resistors are rated according to their maximum power dissipation. Detached resistors in solid-land electronic systems are typically rated every bit 1⁄10 , 1⁄8 , or i⁄4 watt. They usually absorb much less than a watt of electrical ability and require little attending to their power rating.

An aluminium-encased power resistor rated for dissipation of fifty Westward when mounted on a oestrus-sink

Power resistors are required to misemploy substantial amounts of power and are typically used in power supplies, power conversion circuits, and ability amplifiers; this designation is loosely applied to resistors with power ratings of ane watt or greater. Power resistors are physically larger and may non use the preferred values, colour codes, and external packages described beneath.

If the average power dissipated by a resistor is more than its power rating, damage to the resistor may occur, permanently altering its resistance; this is distinct from the reversible change in resistance due to its temperature coefficient when information technology warms. Excessive power dissipation may raise the temperature of the resistor to a point where information technology tin burn the circuit board or next components, or fifty-fifty cause a fire. At that place are flameproof resistors that will non produce flames with whatever overload of any duration.

Resistors may exist specified with higher rated dissipation than is experienced in service to account for poor air circulation, high altitude, or high operating temperature.

All resistors accept a maximum voltage rating; this may limit the ability dissipation for higher resistance values.^[7] For instance, among ane⁄4 watt resistors (a very mutual sort of leaded resistor) i is listed with a resistance of 100 MΩ^[8] and a maximum rated voltage of 750 V. Nonetheless even placing 750 V across a 100 MΩ resistor continuously would but result in a power dissipation of less than vi mW, making the nominal 1⁄4 watt rating meaningless.

VZR power resistor 1.5 kΩ 12 Due west, manufactured in 1963 in the Soviet Union

Nonideal properties

Practical resistors accept a serial inductance and a small parallel capacitance; these specifications can be important in high-frequency applications. In a low-noise amplifier or pre-amp, the noise characteristics of a resistor may exist an consequence.

In some precision applications, the temperature coefficient of the resistance may also be of business organization.

The unwanted inductance, excess noise, and temperature coefficient are mainly dependent on the technology used in manufacturing the resistor. They are non usually specified individually for a particular family of resistors manufactured using a item technology.^[nine] A family of discrete resistors may also be characterized according to its form cistron, that is, the size of the device and the position of its leads (or terminals). This is relevant in the practical manufacturing of circuits that may use them.

Practical resistors are likewise specified as having a maximum ability rating which must exceed the predictable ability dissipation of that resistor in a item excursion: this is mainly of business organization in ability electronics applications. Resistors with higher power ratings are physically larger and may crave oestrus sinks. In a high-voltage excursion, attention must sometimes be paid to the rated maximum working voltage of the resistor. While at that place is no minimum working voltage for a given resistor, failure to account for a resistor's maximum rating may cause the resistor to incinerate when current is run through it.

Fixed resistors

A single in line (SIL) resistor package with 8 individual 47 ohm resistors. This package is besides known equally a SIP-nine. Ane stop of each resistor is continued to a carve up pin and the other ends are all connected together to the remaining (mutual) pin – pin i, at the end identified by the white dot.

Lead arrangements

Axial resistors with wire leads for through-hole mounting

Through-hole components typically take "leads" (pronounced ) leaving the torso "axially", that is, on a line parallel with the part'southward longest axis. Others accept leads coming off their body "radially" instead. Other components may exist SMT (surface mount engineering), while high power resistors may have ane of their leads designed into the heat sink.

Carbon limerick

Quondam fashion "canis familiaris bone" resistors with "torso, tip, dot" colour code marking

Three carbon composition resistors in a 1960s valve (vacuum tube) radio

Carbon composition resistors (CCR) consist of a solid cylindrical resistive element with embedded wire leads or metallic cease caps to which the atomic number 82 wires are attached. The torso of the resistor is protected with paint or plastic. Early on 20th-century carbon composition resistors had uninsulated bodies; the lead wires were wrapped around the ends of the resistance element rod and soldered. The completed resistor was painted for color-coding of its value.

The resistive element in carbon composition resistors is fabricated from a mixture of finely powdered carbon and an insulating material, usually ceramic. A resin holds the mixture together. The resistance is determined by the ratio of the make full material (the powdered ceramic) to the carbon. Higher concentrations of carbon, which is a skillful conductor, result in lower resistances. Carbon composition resistors were unremarkably used in the 1960s and before, but are not popular for general use now every bit other types have ameliorate specifications, such as tolerance, voltage dependence, and stress. Carbon composition resistors change value when stressed with over-voltages. Moreover, if internal moisture content, such every bit from exposure for some length of time to a boiling environment, is meaning, soldering heat creates a not-reversible change in resistance value. Carbon limerick resistors have poor stability with time and were consequently factory sorted to, at best, simply 5% tolerance.^[10] These resistors are non-inductive, which provides benefits when used in voltage pulse reduction and surge protection applications.^[11] Carbon composition resistors take higher capability to withstand overload relative to the component's size.^[12]

Carbon composition resistors are however available, just relatively expensive. Values ranged from fractions of an ohm to 22 megohms. Due to their loftier price, these resistors are no longer used in most applications. Withal, they are used in power supplies and welding controls.^[12] They are also in need for repair of vintage electronic equipment where authenticity is a factor.

Carbon pile

A carbon pile resistor is made of a stack of carbon disks compressed betwixt two metal contact plates. Adjusting the clamping pressure changes the resistance betwixt the plates. These resistors are used when an adaptable load is required, such as in testing automotive batteries or radio transmitters. A carbon pile resistor can also exist used every bit a speed control for small-scale motors in household appliances (sewing machines, hand-held mixers) with ratings up to a few hundred watts.^[13] A carbon pile resistor can be incorporated in automatic voltage regulators for generators, where the carbon pile controls the field current to maintain relatively constant voltage.^[14] This principle is likewise applied in the carbon microphone.

Carbon motion-picture show

Carbon film resistor with exposed carbon spiral (Tesla TR-212 1 kΩ)

In manufacturing carbon film resistors, a carbon film is deposited on an insulating substrate, and a helix is cutting in it to create a long, narrow resistive path. Varying shapes, coupled with the resistivity of amorphous carbon (ranging from 500 to 800 μΩ m), can provide a wide range of resistance values. Carbon picture resistors feature lower noise compared to carbon composition resistors because of the precise distribution of the pure graphite without binding.^[fifteen] Carbon motion picture resistors feature a ability rating range of 0.125 W to 5 W at 70 °C. Resistances available range from 1 ohm to x megaohm. The carbon film resistor has an operating temperature range of −55 °C to 155 °C. It has 200 to 600 volts maximum working voltage range. Special carbon movie resistors are used in applications requiring high pulse stability.^[12]

Printed carbon resistors

Carbon resistors (black rectangles) printed directly onto the SMD pads on the PCB of a Psion Organiser II from 1989

Carbon limerick resistors can be printed straight onto printed circuit board (PCB) substrates as part of the PCB manufacturing process. Although this technique is more common on hybrid PCB modules, information technology can likewise exist used on standard fibreglass PCBs. Tolerances are typically quite large and can be in the order of thirty%. A typical application would be non-disquisitional pull-upward resistors.

Thick and sparse film

Laser Trimmed Precision Sparse Film Resistor Network from Fluke, used in the Keithley DMM7510 multimeter. Ceramic backed with glass hermetic seal embrace.

Thick film resistors became pop during the 1970s, and most SMD (surface mountain device) resistors today are of this type. The resistive element of thick films is thou times thicker than thin films,^[xvi] but the principal deviation is how the film is applied to the cylinder (centric resistors) or the surface (SMD resistors).

Sparse film resistors are made by sputtering (a method of vacuum deposition) the resistive fabric onto an insulating substrate. The film is then etched in a similar fashion to the erstwhile (subtractive) process for making printed circuit boards; that is, the surface is coated with a photo-sensitive cloth, covered by a pattern motion picture, irradiated with ultraviolet lite, and then the exposed photo-sensitive coating is developed, and underlying sparse film is etched away.

Thick film resistors are manufactured using screen and stencil press processes.^[12]

Because the time during which the sputtering is performed can be controlled, the thickness of the sparse film can be accurately controlled. The type of cloth likewise varies, consisting of one or more than ceramic (cermet) conductors such as tantalum nitride (TaN), ruthenium oxide (RuO
₂ ), lead oxide (PbO), bismuth ruthenate (Bi
₂ Ru
₂ O
₇ ), nickel chromium (NiCr), or bismuth iridate (Bi
₂ Ir
₂ O
_vii ).

The resistance of both thin and thick flick resistors after manufacture is not highly accurate; they are usually trimmed to an accurate value by abrasive or laser trimming. Thin pic resistors are ordinarily specified with tolerances of ane% and 5%, and with temperature coefficients of v to 50 ppm/K. They likewise have much lower noise levels, on the level of 10–100 times less than thick moving-picture show resistors.^[17] Thick movie resistors may utilise the same conductive ceramics, but they are mixed with sintered (powdered) drinking glass and a carrier liquid so that the composite tin be screen-printed. This composite of glass and conductive ceramic (cermet) cloth is so fused (baked) in an oven at about 850 °C.

When first manufactured, thick motion-picture show resistors had tolerances of 5%, only standard tolerances take improved to 2% or i% in the concluding few decades.^{[ timeframe? ]} Temperature coefficients of thick film resistors are typically ±200 or ±250 ppm/K; a 40-kelvin (70 °F) temperature change tin change the resistance by ane%.

Thin film resistors are ordinarily far more than expensive than thick film resistors. For instance, SMD thin film resistors, with 0.5% tolerances and with 25 ppm/Grand temperature coefficients, when bought in full size reel quantities, are well-nigh twice the cost of 1%, 250 ppm/Yard thick film resistors.

Metallic picture show

A common type of axial-leaded resistor today is the metal-pic resistor. Metal Electrode Leadless Face up (MELF) resistors often use the aforementioned applied science.

Metal film resistors are unremarkably coated with nickel chromium (NiCr), but might be coated with any of the cermet materials listed above for thin picture show resistors. Unlike sparse film resistors, the material may exist applied using unlike techniques than sputtering (though this is i technique used). The resistance value is determined by cut a helix through the blanket rather than by etching, like to the way carbon resistors are made. The result is a reasonable tolerance (0.5%, ane%, or 2%) and a temperature coefficient that is generally between l and 100 ppm/K.^[eighteen] Metal film resistors possess practiced dissonance characteristics and low not-linearity due to a low voltage coefficient. They are also beneficial due to long-term stability.^[12]

Metallic oxide pic

Metal-oxide motion picture resistors are made of metal oxides which results in a higher operating temperature and greater stability and reliability than metal film. They are used in applications with high endurance demands.

Wire wound

Loftier-power wire wound resistors used for dynamic braking on an electrical railway machine. Such resistors may dissipate many kilowatts for an extended length of fourth dimension.

Wirewound resistors are ordinarily made by winding a metallic wire, usually nichrome, around a ceramic, plastic, or fiberglass core. The ends of the wire are soldered or welded to two caps or rings, fastened to the ends of the core. The assembly is protected with a layer of paint, molded plastic, or an enamel coating baked at high temperature. These resistors are designed to withstand unusually high temperatures of up to 450 °C.^[12] Wire leads in low power wirewound resistors are commonly between 0.half dozen and 0.8 mm in diameter and tinned for ease of soldering. For higher power wirewound resistors, either a ceramic outer case or an aluminum outer case on peak of an insulating layer is used. If the outer instance is ceramic, such resistors are sometimes described every bit "cement" resistors, though they exercise not really contain whatsoever traditional cement. The aluminum-cased types are designed to be attached to a heat sink to dissipate the heat; the rated power is dependent on existence used with a suitable heat sink, e.g., a 50 W ability rated resistor overheats at a fraction of the power dissipation if not used with a heat sink. Large wirewound resistors may be rated for ane,000 watts or more than.

Because wirewound resistors are coils they have more than undesirable inductance than other types of resistor. Yet, winding the wire in sections with alternately reversed direction tin can minimize inductance. Other techniques utilize bifilar winding, or a flat thin old (to reduce cross-section area of the coil). For the most demanding circuits, resistors with Ayrton–Perry winding are used.

Applications of wirewound resistors are similar to those of composition resistors with the exception of high frequency applications. The high frequency response of wirewound resistors is essentially worse than that of a limerick resistor.^[12]

Metal foil resistor

In 1960, Felix Zandman and Sidney J. Stein^[19] presented a development of resistor film of very high stability.

The primary resistance element of a foil resistor is a chromium nickel blend foil several micrometers thick. Chromium nickel alloys are characterized past having a large electrical resistance (nigh 58 times that of copper), a small temperature coefficient and high resistance to oxidation. Examples are Chromel A and Nichrome V, whose typical composition is 80 Ni and 20 Cr, with a melting point of 1420 °C. When fe is added, the chromium nickel alloy becomes more than ductile. The Nichrome and Chromel C are examples of an blend containing iron. The limerick typical of Nichrome is sixty Ni, 12 Cr, 26 Iron, two Mn and Chromel C, 64 Ni, 11 Cr, Fe 25. The melting temperature of these alloys are 1350 °C and 1390 °C, respectively.^{[twenty] [ full citation needed ]}

Since their introduction in the 1960s, foil resistors take had the best precision and stability of any resistor available. 1 of the important parameters of stability is the temperature coefficient of resistance (TCR). The TCR of foil resistors is extremely low, and has been further improved over the years. One range of ultra-precision foil resistors offers a TCR of 0.14 ppm/°C, tolerance ±0.005%, long-term stability (ane yr) 25 ppm, (3 years) 50 ppm (further improved 5-fold by hermetic sealing), stability under load (2000 hours) 0.03%, thermal EMF 0.one μV/°C, racket −42 dB, voltage coefficient 0.one ppm/5, inductance 0.08 μH, capacitance 0.5 pF.^[21]

The thermal stability of this blazon of resistor also has to do with the opposing effects of the metallic'due south electrical resistance increasing with temperature, and being reduced by thermal expansion leading to an increment in thickness of the foil, whose other dimensions are constrained by a ceramic substrate.^{[ citation needed ]}

Ammeter shunts

An ammeter shunt is a special blazon of current-sensing resistor, having four terminals and a value in milliohms or even micro-ohms. Current-measuring instruments, by themselves, can usually have merely limited currents. To measure loftier currents, the electric current passes through the shunt across which the voltage drop is measured and interpreted as electric current. A typical shunt consists of ii solid metal blocks, sometimes contumely, mounted on an insulating base. Between the blocks, and soldered or brazed to them, are 1 or more strips of low temperature coefficient of resistance (TCR) manganin blend. Large bolts threaded into the blocks make the current connections, while much smaller screws provide volt meter connections. Shunts are rated past full-scale current, and oftentimes have a voltage drop of l mV at rated current. Such meters are adapted to the shunt full current rating by using an appropriately marked punch face; no change need to be fabricated to the other parts of the meter.

Grid resistor

In heavy-duty industrial high-current applications, a filigree resistor is a big convection-cooled lattice of stamped metal alloy strips connected in rows between two electrodes. Such industrial grade resistors can be as large every bit a refrigerator; some designs can handle over 500 amperes of current, with a range of resistances extending lower than 0.04 ohms. They are used in applications such as dynamic braking and load cyberbanking for locomotives and trams, neutral grounding for industrial AC distribution, control loads for cranes and heavy equipment, load testing of generators and harmonic filtering for electrical substations.^[22]

The term grid resistor is sometimes used to describe a resistor of any type connected to the control grid of a vacuum tube. This is non a resistor technology; it is an electronic circuit topology.

Special varieties

• Cermet
• Phenolic
• Tantalum
• Water resistor

Variable resistors

Adaptable resistors

A resistor may have 1 or more stock-still borer points and so that the resistance tin exist inverse past moving the connecting wires to dissimilar terminals. Some wirewound power resistors have a tapping point that can slide along the resistance element, allowing a larger or smaller part of the resistance to exist used.

Where continuous adjustment of the resistance value during operation of equipment is required, the sliding resistance tap can be connected to a knob accessible to an operator. Such a device is called a rheostat and has 2 terminals.

Potentiometers

Typical panel mountain potentiometer

Cartoon of potentiometer with example cutting away, showing parts: (A) shaft, (B) stationary carbon composition resistance element, (C) phosphor bronze wiper, (D) shaft attached to wiper, (E, Yard) terminals connected to ends of resistance element, (F) terminal connected to wiper.

A potentiometer (colloquially, pot) is a three-concluding resistor with a continuously adjustable tapping point controlled by rotation of a shaft or knob or by a linear slider.^[23] The proper name potentiometer comes from its office as an adjustable voltage divider to provide a variable potential at the terminal connected to the tapping bespeak. Book control in an audio device is a common application of a potentiometer. A typical low power potentiometer (run across drawing) is constructed of a flat resistance element (B) of carbon composition, metal film, or conductive plastic, with a springy phosphor bronze wiper contact (C) which moves along the surface. An alternating construction is resistance wire wound on a class, with the wiper sliding axially forth the coil.^[23] These take lower resolution, since equally the wiper moves the resistance changes in steps equal to the resistance of a single plow.^[23]

High-resolution multiturn potentiometers are used in precision applications. These have wire-wound resistance elements typically wound on a helical mandrel, with the wiper moving on a helical rail as the control is turned, making continuous contact with the wire. Some include a conductive-plastic resistance coating over the wire to improve resolution. These typically offer x turns of their shafts to cover their total range. They are usually set with dials that include a simple turns counter and a graduated dial, and tin typically achieve iii-digit resolution. Electronic analog computers used them in quantity for setting coefficients and delayed-sweep oscilloscopes of recent decades included one on their panels.

Resistance decade boxes

A resistance decade box or resistor substitution box is a unit containing resistors of many values, with ane or more than mechanical switches which allow any one of various detached resistances offered past the box to be dialed in. Usually the resistance is accurate to loftier precision, ranging from laboratory/calibration grade accuracy of 20 parts per million, to field grade at ane%. Cheap boxes with lesser accuracy are also available. All types offer a convenient way of selecting and rapidly irresolute a resistance in laboratory, experimental and development work without needing to adhere resistors one past 1, or even stock each value. The range of resistance provided, the maximum resolution, and the accurateness narrate the box. For example, one box offers resistances from 0 to 100 megohms, maximum resolution 0.1 ohm, accuracy 0.one%.^[24]

Special devices

There are various devices whose resistance changes with diverse quantities. The resistance of NTC thermistors exhibit a strong negative temperature coefficient, making them useful for measuring temperatures. Since their resistance can exist large until they are allowed to heat up due to the passage of electric current, they are as well usually used to prevent excessive electric current surges when equipment is powered on. Similarly, the resistance of a humistor varies with humidity. One sort of photodetector, the photoresistor, has a resistance which varies with illumination.

The strain judge, invented past Edward E. Simmons and Arthur C. Ruge in 1938, is a type of resistor that changes value with applied strain. A single resistor may be used, or a pair (half bridge), or four resistors connected in a Wheatstone span configuration. The strain resistor is bonded with agglutinative to an object that is subjected to mechanical strain. With the strain gauge and a filter, amplifier, and analog/digital converter, the strain on an object tin exist measured.

A related but more contempo invention uses a Quantum Tunnelling Composite to sense mechanical stress. It passes a current whose magnitude can vary by a gene of 10¹² in response to changes in applied pressure.

Measurement

The value of a resistor can be measured with an ohmmeter, which may exist one function of a multimeter. Usually, probes on the ends of test leads connect to the resistor. A uncomplicated ohmmeter may apply a voltage from a battery across the unknown resistor (with an internal resistor of a known value in serial) producing a current which drives a meter movement. The electric current, in accordance with Ohm's law, is inversely proportional to the sum of the internal resistance and the resistor existence tested, resulting in an analog meter scale which is very non-linear, calibrated from infinity to 0 ohms. A digital multimeter, using active electronics, may instead pass a specified current through the test resistance. The voltage generated across the test resistance in that example is linearly proportional to its resistance, which is measured and displayed. In either case the low-resistance ranges of the meter pass much more current through the exam leads than do high-resistance ranges. This allows for the voltages present to be at reasonable levels (generally below x volts) simply nonetheless measurable.

Measuring low-value resistors, such as fractional-ohm resistors, with adequate accuracy requires 4-concluding connections. One pair of terminals applies a known, calibrated current to the resistor, while the other pair senses the voltage drop beyond the resistor. Some laboratory quality ohmmeters, milliohmmeters, and even some of the better digital multimeters sense using four input terminals for this purpose, which may be used with special test leads called Kelvin clips. Each of the two clips has a pair of jaws insulated from each other. One side of each clip applies the measuring current, while the other connections are only to sense the voltage drop. The resistance is over again calculated using Ohm's Law as the measured voltage divided by the applied current.

Standards

Product resistors

Resistor characteristics are quantified and reported using diverse national standards. In the US, MIL-STD-202^[25] contains the relevant exam methods to which other standards refer.

There are various standards specifying properties of resistors for use in equipment:

• IEC 60062 (IEC 62) / DIN 40825 / BS 1852 / IS 8186 / JIS C 5062 etc. (Resistor colour code, RKM code, engagement code)
• Eia RS-279 / DIN 41429 (Resistor color lawmaking)
• IEC 60063 (IEC 63) / JIS C 5063 (Standard E series values)
• MIL-PRF-26
• MIL-PRF-39007 (Stock-still power, established reliability)
• MIL-PRF-55342 (Surface-mountain thick and thin film)
• MIL-PRF-914
• MIL-R-xi Standard Canceled
• MIL-R-39017 (Fixed, General Purpose, Established Reliability)
• MIL-PRF-32159 (zero ohm jumpers)
• UL 1412 (fusing and temperature limited resistors)^[26]

There are other United states of america military procurement MIL-R- standards.

Resistance standards

The principal standard for resistance, the "mercury ohm" was initially divers in 1884 in as a column of mercury 106.3 cm long and 1 foursquare millimeter in cross-section, at 0 degrees Celsius. Difficulties in precisely measuring the physical constants to replicate this standard issue in variations of as much as xxx ppm. From 1900 the mercury ohm was replaced with a precision machined plate of manganin.^[27] Since 1990 the international resistance standard has been based on the quantized Hall outcome discovered by Klaus von Klitzing, for which he won the Nobel Prize in Physics in 1985.^[28]

Resistors of extremely loftier precision are manufactured for calibration and laboratory use. They may accept four terminals, using i pair to conduct an operating current and the other pair to measure the voltage drop; this eliminates errors caused by voltage drops across the lead resistances, because no accuse flows through voltage sensing leads. It is important in small value resistors (100–0.0001 ohm) where lead resistance is pregnant or even comparable with respect to resistance standard value.^[29]

Resistor marking

Bike-based RMA Resistor Color Code guide. Circa 1945–1950.

Axial resistors' cases are ordinarily tan, brown, blue, or green (though other colors are occasionally found also, such every bit nighttime red or dark gray), and display 3–6 colored stripes that point resistance (and by extension tolerance), and may include bands to signal the temperature coefficient and reliability class. In four-striped resistors, the first two stripes represent the first two digits of the resistance in ohms, the third represents a multiplier, and the fourth the tolerance (which if absent, denotes ±20%). For five- and half dozen- striped resistors the third band is the third digit, the fourth is the multiplier and the fifth is the tolerance; a 6th stripe represents the temperature coefficient. The power rating of the resistor is usually not marked and is deduced from its size.

Surface-mount resistors are marked numerically.

Early 20th century resistors, essentially uninsulated, were dipped in pigment to cover their entire torso for color-coding. This base color represented the starting time digit. A second color of paint was applied to ane end of the element to represent a second digit, and a colour dot (or band) in the middle provided the third digit. The rule was "torso, tip, dot", providing two significant digits for value and the decimal multiplier, in that sequence. Default tolerance was ±20%. Closer-tolerance resistors had silver (±10%) or gold-colored (±5%) paint on the other stop.

Preferred values

Early on resistors were made in more than or less arbitrary round numbers; a series might have 100, 125, 150, 200, 300, etc.^[30] Early on power wirewound resistors, such as dark-brown vitreous-enameled types, were made with a system of preferred values like some of those mentioned here. Resistors as manufactured are field of study to a certain percentage tolerance, and information technology makes sense to manufacture values that correlate with the tolerance, so that the actual value of a resistor overlaps slightly with its neighbors. Wider spacing leaves gaps; narrower spacing increases manufacturing and inventory costs to provide resistors that are more or less interchangeable.

A logical scheme is to produce resistors in a range of values which increase in a geometric progression, so that each value is greater than its predecessor by a stock-still multiplier or percentage, chosen to match the tolerance of the range. For instance, for a tolerance of ±xx% it makes sense to take each resistor about i.v times its predecessor, covering a decade in 6 values. More precisely, the factor used is 1.4678 ≈ ${\displaystyle 10^{one/6}}$ , giving values of 1.47, 2.15, 3.16, 4.64, 6.81, 10 for the one–10-decade (a decade is a range increasing by a factor of 10; 0.i–1 and 10–100 are other examples); these are rounded in practice to 1.v, 2.2, three.iii, iv.7, 6.8, 10; followed by 15, 22, 33, ... and preceded past ... 0.47, 0.68, 1. This scheme has been adopted as the E6 serial of the IEC 60063 preferred number values. There are also E12, E24, E48, E96 and E192 series for components of progressively finer resolution, with 12, 24, 48, 96, and 192 different values inside each decade. The actual values used are in the IEC 60063 lists of preferred numbers.

A resistor of 100 ohms ±20% would be expected to take a value between 80 and 120 ohms; its E6 neighbors are 68 (54–82) and 150 (120–180) ohms. A sensible spacing, E6 is used for ±20% components; E12 for ±x%; E24 for ±five%; E48 for ±2%, E96 for ±1%; E192 for ±0.5% or better. Resistors are manufactured in values from a few milliohms to about a gigaohm in IEC60063 ranges advisable for their tolerance. Manufacturers may sort resistors into tolerance-classes based on measurement. Accordingly, a selection of 100 ohms resistors with a tolerance of ±10%, might not lie just around 100 ohm (but no more ten% off) as i would wait (a bell-curve), but rather exist in 2 groups – either betwixt v and 10% also loftier or 5 to x% besides low (but not closer to 100 ohm than that) because any resistors the factory had measured as existence less than five% off would have been marked and sold as resistors with just ±five% tolerance or better. When designing a excursion, this may become a consideration. This procedure of sorting parts based on post-production measurement is known every bit "binning", and can be applied to other components than resistors (such as speed grades for CPUs).

SMT resistors

This image shows four surface-mount resistors (the component at the upper left is a capacitor) including ii zero-ohm resistors. Nix-ohm links are oft used instead of wire links, and so that they can be inserted past a resistor-inserting machine. Their resistance is negligible.

Surface mounted resistors of larger sizes (metric 1608 and above) are printed with numerical values in a code related to that used on centric resistors. Standard-tolerance surface-mount technology (SMT) resistors are marked with a three-digit code, in which the first two digits are the first two significant digits of the value and the third digit is the power of ten (the number of zeroes). For case:

• 334 = 33 × 10^iv Ω = 330 kΩ
• 222 = 22 × 10² Ω = two.2 kΩ
• 473 = 47 × 10³ Ω = 47 kΩ
• 105 = 10 × ten⁵ Ω = 1 MΩ

Resistances less than 100 Ω are written: 100, 220, 470. The final zero represents ten to the power nil, which is ane. For case:

• 100 = x × 10⁰ Ω = 10 Ω
• 220 = 22 × 10⁰ Ω = 22 Ω

Sometimes these values are marked as ten or 22 to prevent a mistake.

Resistances less than 10 Ω have 'R' to signal the position of the decimal betoken (radix point). For example:

• 4R7 = iv.7 Ω
• R300 = 0.30 Ω
• 0R22 = 0.22 Ω
• 0R01 = 0.01 Ω

000 and 0000 sometimes announced as values on surface-mount goose egg-ohm links, since these accept (approximately) zero resistance.

More contempo surface-mount resistors are as well pocket-sized, physically, to allow practical markings to be applied.

Precision resistor markings

Many precision resistors, including surface mountain and centric-lead types, are marked with a iv-digit lawmaking. The outset three digits are the meaning figures and the fourth is the power of ten. For case:

• 1001 = 100 × 10¹ Ω = 1.00 kΩ
• 4992 = 499 × x^two Ω = 49.nine kΩ
• 1000 = 100 × x⁰ Ω = 100 Ω

Axial-atomic number 82 precision resistors frequently use color code bands to correspond this four-digit code.

Environmental impact assessment-96 marker

The quondam EIA-96 marking arrangement now included in IEC 60062:2016 is a more compact mark system intended for physically minor high-precision resistors. Information technology uses a two-digit code plus a letter of the alphabet (a full of three alphanumeric characters) to signal one% resistance values to 3 significant digits.^[31] The two digits (from "01" to "96") are a lawmaking that indicates 1 of the 96 "positions" in the standard E96 series of 1% resistor values. The majuscule letter is a code that indicates a power of ten multiplier. For case, the marking "01C" represents x kOhm; "10C" represents 12.4 kOhm; "96C" represents 97.6 kOhm.^{[32] [33] [34] [35] [36]}

Code Series Letter Digits E96 Y / S X / R A B / H C D E 01 ane.00 1R00 10R0 100R 1K00 10K0 100K 1M00 02 one.02 1R02 10R2 102R 1K02 10K2 102K 1M02 03 one.05 1R05 10R5 105R 1K05 10K5 105K 1M05 04 i.07 1R07 10R7 107R 1K07 10K7 107K 1M07 05 1.ten 1R10 11R0 110R 1K10 11K0 110K 1M10 06 i.13 1R13 11R3 113R 1K13 11K3 113K 1M13 07 1.15 1R15 11R5 115R 1K15 11K5 115K 1M15 08 1.18 1R18 11R8 118R 1K18 11K8 118K 1M18 09 1.21 1R21 12R1 121R 1K21 12K1 121K 1M21 10 i.24 1R24 12R4 124R 1K24 12K4 124K 1M24 xi ane.27 1R27 12R7 127R 1K27 12K7 127K 1M27 12 1.thirty 1R30 13R0 130R 1K30 13K0 130K 1M30 xiii 1.33 1R33 13R3 133R 1K33 13K3 133K 1M33 xiv 1.37 1R37 13R7 137R 1K37 13K7 137K 1M37 xv 1.twoscore 1R40 14R0 140R 1K40 14K0 140K 1M40 16 ane.43 1R43 14R3 143R 1K43 14K3 143K 1M43 17 one.47 1R47 14R7 147R 1K47 14K7 147K 1M47 18 1.50 1R50 15R0 150R 1K50 15K0 150K 1M50 19 one.54 1R54 15R4 154R 1K54 15K4 154K 1M54 xx 1.58 1R58 15R8 158R 1K58 15K8 158K 1M58 21 1.62 1R62 16R2 162R 1K62 16K2 162K 1M62 22 1.65 1R65 16R5 165R 1K65 16K5 165K 1M65 23 1.69 1R69 16R9 169R 1K69 16K9 169K 1M69 24 1.74 1R74 17R4 174R 1K74 17K4 174K 1M74 25 1.78 1R78 17R8 178R 1K78 17K8 178K 1M78 26 1.82 1R82 18R2 182R 1K82 18K2 182K 1M82 27 one.87 1R87 18R7 187R 1K87 18K7 187K 1M87 28 one.91 1R91 19R1 191R 1K91 19K1 191K 1M91 29 1.96 1R96 19R6 196R 1K96 19K6 196K 1M96 30 2.00 2R00 20R0 200R 2K00 20K0 200K 2M00 31 2.05 2R05 20R5 205R 2K05 20K5 205K 2M05 32 two.x 2R10 21R0 210R 2K10 21K0 210K 2M10 33 two.15 2R15 21R5 215R 2K15 21K5 215K 2M15 34 ii.21 2R21 22R1 221R 2K21 22K1 221K 2M21 35 2.26 2R26 22R6 226R 2K26 22K6 226K 2M26 36 ii.32 2R32 23R2 232R 2K32 23K2 232K 2M32 37 2.37 2R37 23R7 237R 2K37 23K7 237K 2M37 38 2.43 2R43 24R3 243R 2K43 24K3 243K 2M43 39 2.49 2R49 24R9 249R 2K49 24K9 249K 2M49 40 2.55 2R55 25R5 255R 2K55 25K5 255K 2M55 41 ii.61 2R61 26R1 261R 2K61 26K1 261K 2M61 42 2.67 2R67 26R7 267R 2K67 26K7 267K 2M67 43 2.74 2R74 27R4 274R 2K74 27K4 274K 2M74 44 2.lxxx 2R80 28R0 280R 2K80 28K0 280K 2M80 45 two.87 2R87 28R7 287R 2K87 28K7 287K 2M87 46 2.94 2R94 29R4 294R 2K94 29K4 294K 2M94 47 3.01 3R01 30R1 301R 3K01 30K1 301K 3M01 48 3.09 3R09 30R9 309R 3K09 30K9 309K 3M09

Code Series Letter of the alphabet Digits E96 Y / South Ten / R A B / H C D E 49 iii.sixteen 3R16 31R6 316R 3K16 31K6 316K 3M16 l 3.24 3R24 32R4 324R 3K24 32K4 324K 3M24 51 3.32 3R32 33R2 332R 3K32 33K2 332K 3M32 52 3.40 3R40 34R0 340R 3K40 34K0 340K 3M40 53 3.48 3R48 34R8 348R 3K48 34K8 348K 3M48 54 three.57 3R57 35R7 357R 3K57 35K7 357K 3M57 55 iii.65 3R65 36R5 365R 3K65 36K5 365K 3M65 56 three.74 3R74 37R4 374R 3K74 37K4 374K 3M74 57 3.83 3R83 38R3 383R 3K83 38K3 383K 3M83 58 3.92 3R92 39R2 392R 3K92 39K2 392K 3M92 59 4.02 4R02 40R2 402R 4K02 40K2 402K 4M02 60 4.12 4R12 41R2 412R 4K12 41K2 412K 4M12 61 4.22 4R22 42R2 422R 4K22 42K2 422K 4M22 62 four.32 4R32 43R2 432R 4K32 43K2 432K 4M32 63 4.42 4R42 44R2 442R 4K42 44K2 442K 4M42 64 four.53 4R53 45R3 453R 4K53 45K3 453K 4M53 65 4.64 4R64 46R4 464R 4K64 46K4 464K 4M64 66 iv.75 4R75 47R5 475R 4K75 47K5 475K 4M75 67 4.87 4R87 48R7 487R 4K87 48K7 487K 4M87 68 4.99 4R99 49R9 499R 4K99 49K9 499K 4M99 69 5.xi 5R11 51R1 511R 5K11 51K1 511K 5M11 lxx 5.23 5R23 52R3 523R 5K23 52K3 523K 5M23 71 v.36 5R36 53R6 536R 5K36 53K6 536K 5M36 72 5.49 5R49 54R9 549R 5K49 54K9 549K 5M49 73 v.62 5R62 56R2 562R 5K62 56K2 562K 5M62 74 5.76 5R76 57R6 576R 5K76 57K6 576K 5M76 75 5.90 5R90 59R0 590R 5K90 59K0 590K 5M90 76 6.04 6R04 60R4 604R 6K04 60K4 604K 6M04 77 6.19 6R19 61R9 619R 6K19 61K9 619K 6M19 78 6.34 6R34 63R4 634R 6K34 63K4 634K 6M34 79 half dozen.49 6R49 64R9 649R 6K49 64K9 649K 6M49 80 6.65 6R65 66R5 665R 6K65 66K5 665K 6M65 81 half-dozen.81 6R81 68R1 681R 6K81 68K1 681K 6M81 82 vi.98 6R98 69R8 698R 6K98 69K8 698K 6M98 83 7.15 7R15 71R5 715R 7K15 71K5 715K 7M15 84 7.32 7R32 73R2 732R 7K32 73K2 732K 7M32 85 7.50 7R50 75R0 750R 7K50 75K0 750K 7M50 86 seven.68 7R68 76R8 768R 7K68 76K8 768K 7M68 87 seven.87 7R87 78R7 787R 7K87 78K7 787K 7M87 88 eight.06 8R06 80R6 806R 8K06 80K6 806K 8M06 89 8.25 8R25 82R5 825R 8K25 82K5 825K 8M25 90 eight.45 8R45 84R5 845R 8K45 84K5 845K 8M45 91 8.66 8R66 86R6 866R 8K66 86K6 866K 8M66 92 8.87 8R87 88R7 887R 8K87 88K7 887K 8M87 93 9.09 9R09 90R9 909R 9K09 90K9 909K 9M09 94 9.31 9R31 93R1 931R 9K31 93K1 931K 9M31 95 9.53 9R53 95R3 953R 9K53 95K3 953K 9M53 96 nine.76 9R76 97R6 976R 9K76 97K6 976K 9M76

Industrial type designation

Ability Rating at 70 °C

Type no.	Power rating (watts)	MIL-R-eleven style	MIL-R-39008 style
BB	one⁄8	RC05	RCR05
CB	1⁄four	RC07	RCR07
EB	1⁄2	RC20	RCR20
GB	ane	RC32	RCR32
HB	2	RC42	RCR42
GM	iii	-	-
HM	4	-	-

Tolerance code

Industrial type designation	Tolerance	MIL designation
5	±5%	J
ii	±twenty%	1000
1	±x%	One thousand
-	±ii%	G
-	±1%	F
-	±0.5%	D
-	±0.25%	C
-	±0.1%	B

Steps to notice out the resistance or capacitance values:^[37]

1. First ii letters gives the power dissipation capacity.
2. Side by side iii digits gives the resistance value.
   1. First two digits are the meaning values
   2. Third digit is the multiplier.
3. Final digit gives the tolerance.

If a resistor is coded:

• EB1041: power dissipation capacity = 1/2 watts, resistance value = x×10⁴ ±x% = between 9×10⁴ ohms and 11×x⁴ ohms.
• CB3932: power dissipation capacity = ane/iv watts, resistance value = 39×ten³ ±20% = between 31.two×10³ and 46.8×10³ ohms.

Electric and thermal noise

In amplifying faint signals, information technology is oft necessary to minimize electronic noise, particularly in the first stage of amplification. As a dissipative element, even an ideal resistor naturally produces a randomly fluctuating voltage, or noise, across its terminals. This Johnson–Nyquist noise is a fundamental noise source which depends only upon the temperature and resistance of the resistor, and is predicted by the fluctuation–dissipation theorem. Using a larger value of resistance produces a larger voltage racket, whereas a smaller value of resistance generates more electric current noise, at a given temperature.

The thermal noise of a practical resistor may also be larger than the theoretical prediction and that increment is typically frequency-dependent. Excess noise of a applied resistor is observed simply when current flows through it. This is specified in unit of μV/Five/decade – μV of noise per volt applied across the resistor per decade of frequency. The μV/Five/decade value is frequently given in dB then that a resistor with a noise alphabetize of 0 dB exhibits 1 μV (rms) of excess noise for each volt across the resistor in each frequency decade. Excess dissonance is thus an example of 1/f noise. Thick-motion picture and carbon composition resistors generate more excess noise than other types at low frequencies. Wire-wound and thin-film resistors are often used for their improve noise characteristics. Carbon limerick resistors can showroom a noise index of 0 dB while majority metallic foil resistors may have a racket index of −40 dB, usually making the backlog noise of metal foil resistors insignificant.^[38] Thin picture show surface mount resistors typically have lower noise and better thermal stability than thick film surface mount resistors. Excess racket is besides size-dependent: in general, excess noise is reduced as the physical size of a resistor is increased (or multiple resistors are used in parallel), every bit the independently fluctuating resistances of smaller components tend to average out.

While not an example of "noise" per se, a resistor may deed as a thermocouple, producing a pocket-size DC voltage differential across it due to the thermoelectric effect if its ends are at dissimilar temperatures. This induced DC voltage can dethrone the precision of instrumentation amplifiers in detail. Such voltages appear in the junctions of the resistor leads with the circuit board and with the resistor body. Common metal film resistors show such an effect at a magnitude of nearly 20 μV/°C. Some carbon composition resistors can exhibit thermoelectric offsets as high as 400 μV/°C, whereas specially constructed resistors can reduce this number to 0.05 μV/°C. In applications where the thermoelectric result may become important, care has to be taken to mount the resistors horizontally to avoid temperature gradients and to mind the air flow over the board.^[39]

Failure modes

The failure rate of resistors in a properly designed circuit is low compared to other electronic components such equally semiconductors and electrolytic capacitors. Damage to resistors virtually often occurs due to overheating when the average ability delivered to it greatly exceeds its ability to dissipate heat (specified by the resistor's ability rating). This may be due to a error external to the excursion but is frequently acquired by the failure of some other component (such as a transistor that shorts out) in the circuit continued to the resistor. Operating a resistor also close to its power rating can limit the resistor's lifespan or cause a meaning change in its resistance. A safety design by and large uses overrated resistors in power applications to avert this danger.

Low-power thin-film resistors can be damaged by long-term high-voltage stress, even below maximum specified voltage and below maximum power rating. This is ofttimes the case for the startup resistors feeding a switched-mode power supply integrated excursion.^{[ citation needed ]}

When overheated, carbon-picture show resistors may subtract or increase in resistance.^[xl] Carbon moving picture and composition resistors can neglect (open circuit) if running close to their maximum dissipation. This is also possible but less likely with metal moving picture and wirewound resistors.

There tin can also be failure of resistors due to mechanical stress and agin environmental factors including humidity. If not enclosed, wirewound resistors can corrode.

Surface mount resistors accept been known to fail due to the ingress of sulfur into the internal makeup of the resistor. This sulfur chemically reacts with the silvery layer to produce non-conductive silver sulfide. The resistor's impedance goes to infinity. Sulfur resistant and anti-corrosive resistors are sold into automotive, industrial, and armed services applications. ASTM B809 is an industry standard that tests a part'south susceptibility to sulfur.

An culling failure mode can be encountered where large value resistors are used (hundreds of kilohms and higher). Resistors are not merely specified with a maximum ability dissipation, but also for a maximum voltage drop. Exceeding this voltage causes the resistor to degrade slowly reducing in resistance. The voltage dropped across large value resistors can be exceeded before the power dissipation reaches its limiting value. Since the maximum voltage specified for unremarkably encountered resistors is a few hundred volts, this is a problem just in applications where these voltages are encountered.

Variable resistors can also dethrone in a different manner, typically involving poor contact between the wiper and the trunk of the resistance. This may be due to clay or corrosion and is typically perceived every bit "crackling" as the contact resistance fluctuates; this is peculiarly noticed as the device is adjusted. This is similar to crackling caused by poor contact in switches, and like switches, potentiometers are to some extent self-cleaning: running the wiper across the resistance may improve the contact. Potentiometers which are seldom adapted, especially in dirty or harsh environments, are about likely to develop this trouble. When cocky-cleaning of the contact is bereft, improvement can commonly exist obtained through the apply of contact cleaner (also known as "tuner cleaner") spray. The crackling racket associated with turning the shaft of a muddy potentiometer in an audio circuit (such as the volume control) is greatly accentuated when an undesired DC voltage is present, often indicating the failure of a DC blocking capacitor in the excursion.

Run across also

• Excursion design
• Dummy load
• Electrical impedance
• High value resistors (electronics)
• Iron-hydrogen resistor
• Piezoresistive outcome
• Shot dissonance
• Thermistor
• Trimmer (electronics)

References

1. ^ Harder, Douglas Wilhelm. "Resistors: A Motor with a Constant Forcefulness (Force Source)". Department of Electrical and Reckoner Technology, University of Waterloo. Retrieved ix Nov 2014.
2. ^ American Radio Relay League (ARRL) (2021). "Fundamental Theory—Circuits and Components". ARRL Handbook for Radio Communications (98 ed.). American Radio Relay League. ISBN978-one-62595-139-7.
3. ^ ^{a b c} Doug DeMaw, ed. (1968). "Electric Laws and Circuits —Resistance". Radio Amateurs Handbook (45 ed.). American Radio Relay League.
4. ^ Farago, P.Due south. (1961) An Introduction to Linear Network Assay, pp. 18–21, The English language Universities Press Ltd.
5. ^ Wu, F. Y. (2004). "Theory of resistor networks: The two-point resistance". Journal of Physics A: Mathematical and General. 37 (26): 6653–6673. arXiv:math-ph/0402038. Bibcode:2004JPhA...37.6653W. doi:x.1088/0305-4470/37/26/004. S2CID 119611570.
6. ^ Wu, Fa Yueh; Yang, Chen Ning (2009). Exactly Solved Models: A Journey in Statistical Mechanics : Selected Papers with Commentaries (1963–2008). World Scientific. pp. 489–. ISBN978-981-281-388-6.
7. ^ "Specifications and How to Interpret Them" (PDF). Stackpole Electronics. Retrieved July 6, 2021.
8. ^ https://nl.farnell.com/te-connectivity/rgp0207chj100m/res-100m-5-250mw-axial-thick-movie/dp/2805251^{[ bare URL ]}
9. ^ A family of resistors may as well exist characterized according to its critical resistance. Applying a constant voltage across resistors in that family below the disquisitional resistance volition exceed the maximum power rating first; resistances larger than the critical resistance neglect first from exceeding the maximum voltage rating. See Middleton, Wendy; Van Valkenburg, Mac Eastward. (2002). Reference data for engineers: radio, electronics, reckoner, and communications (ix ed.). Newnes. pp. 5–ten. ISBN0-7506-7291-9.
10. ^ Harter, James H. and Lin, Paul Y. (1982) Essentials of electric circuits. Reston Publishing Company. pp. 96–97. ISBN 0-8359-1767-iii.
11. ^ HVR International (ed.). "SR Series: Surge Resistors for PCB Mounting". (PDF; 252 kB), 26 May 2005, retrieved 24 January 2017.
12. ^ ^{a b c d e f chiliad} Beyschlag, Vishay (2008). "Nuts of Linear Fixed Resistors Application Note", Document Number 28771.
13. ^ Morris, C. Thousand. (ed.) (1992). Bookish Press Dictionary of Science and Applied science. Gulf Professional Publishing. p. 360. ISBN 0122004000.
14. ^ Principles of automotive vehicles. U.s.a. Department of the Army (1985). p. 13
15. ^ "Carbon Moving picture Resistor". The Resistorguide . Retrieved x March 2013.
16. ^ "Thick Moving-picture show and Thin Picture" (PDF). Digi-Key (SEI). Archived from the original (PDF) on 27 September 2011. Retrieved 23 July 2011.
17. ^ "Thin and Thick film". resisitorguide.com. resistor guide. Retrieved iii December 2017.
18. ^ Kuhn, Kenneth A. "Measuring the Temperature Coefficient of a Resistor" (PDF). Archived from the original (PDF) on 2016-03-04. Retrieved 2010-03-18 .
19. ^ Zandman, F.; Stein, S. (1964). "A New Precision Moving-picture show Resistor Exhibiting Bulk Properties". IEEE Transactions on Component Parts. 11 (ii): 107–119. doi:x.1109/TCP.1964.1135008.
20. ^ Procedures in Experimental Physics, John Strong, p. 546.
21. ^ "Alpha Electronics Corp. Metal Foil Resistors". Alpha-elec.co.jp. Retrieved 2008-09-22 .
22. ^ "Grid Resistors: High Ability/High Current". Milwaukee Resistor Corporation. Retrieved 14 May 2012.
23. ^ ^{a b c} Mazda, F. F. (1981). Discrete Electronic Components. Cup Archive. pp. 57–61. ISBN0521234700.
24. ^ "Decade Box – Resistance Decade Boxes". Ietlabs.com. Retrieved 2008-09-22 .
25. ^ "Examination method standard: electronic and electrical component parts" (PDF). Department of Defense. Archived from the original (PDF) on 2015-02-09.
26. ^ Fusing Resistors and Temperature-Limited Resistors for Radio- and Idiot box- Type Appliances UL 1412. ulstandardsinfonet.ul.com
27. ^ Stability of Double-Walled Manganin Resistors Archived 2006-10-06 at the Wayback Machine. NIST.gov
28. ^ Klaus von Klitzing The Quantized Hall Outcome. Nobel lecture, December nine, 1985. nobelprize.org
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31. ^ "Affiliate 2 - Resistor standards and codes".
32. ^ "CRP0603 Series - Precision Bit Resistors". p. iii.
33. ^ "Online calculator - Eia-96 SMD resistor".
34. ^ "SMD Resistor Codes: How to Discover the Value of SMD Resistors".
35. ^ "Marker Codes used on Welwyn Chip Resistors". p. ii.
36. ^ "Surface Mount Resistor: codes & markings".
37. ^ Maini, A. Grand. (2008), Electronics and Communications Simplified, ninth ed., Khanna Publications. ISBN 817409217X
38. ^ Audio Noise Reduction Through the Use of Bulk Metal Foil Resistors – "Hear the Difference" (PDF). Archived from the original (PDF) on 2013-01-19. Retrieved 2009-08-03 . , Application annotation AN0003, Vishay Intertechnology Inc, 12 July 2005.
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External links

Look up resistor in Wiktionary, the costless dictionary.

• 4-terminal resistors – How ultra-precise resistors work
• Beginner's guide to potentiometers, including clarification of unlike tapers
• Color Coded Resistance Calculator – archived with WayBack Machine
• Resistor Types – Does It Matter?
• Standard Resistors & Capacitor Values That Manufacture Manufactures
• Ask The Applications Engineer – Difference between types of resistors
• Resistors and their uses

24 Ohm 6 Watt Resistor,

Source: https://en.wikipedia.org/wiki/Resistor

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