{"id":24068,"date":"2026-10-09T08:51:15","date_gmt":"2026-10-09T08:51:15","guid":{"rendered":"https:\/\/lead-pcb.com\/?p=24068"},"modified":"2026-10-21T07:38:21","modified_gmt":"2026-10-21T07:38:21","slug":"smd-resistor","status":"publish","type":"post","link":"https:\/\/lead-pcb.com\/fr\/blog\/smd-resistor\/","title":{"rendered":"SMD Resistor Guide: Codes, Sizes, Footprints and Limits"},"content":{"rendered":"<p class=\"wp-block-paragraph\">Un <strong>SMD resistor<\/strong> is a fixed-value resistor in a leadless rectangular package that solders to pads on the surface of a printed circuit board rather than passing through holes. It is typically the most numerous component on a board, and the one most often specified from habit rather than from the datasheet.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Most guides to these parts stop at two questions: what size is it, and what does the code mean. Both matter, and both are answered below. But they are not the questions that get a design into trouble. A chip resistor&#8217;s published power rating is not the power it can dissipate in your product. Its package code is not a power rating at all. And the pad dimensions underneath it decide whether it solders reliably, which no package table tells you.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This guide covers the four decoding systems, a sourced package and voltage table, thermal derating with a worked calculation, land pattern geometry, and how package size changes what an assembly line can actually place and inspect.<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\"><strong>Points cl\u00e9s<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>A chip resistor&#8217;s published wattage applies at 70 \u00b0C ambient and derates linearly to zero at the part&#8217;s upper category temperature. A 0603 rated 0.1 W is not a 0.1 W part inside a hot enclosure.<\/li>\n\n\n\n<li>The four-digit package code is a footprint in hundredths of an inch, not a power rating. Power belongs to the series and the manufacturer, which is why two datasheets can both be right and still print different numbers for a 1206.<\/li>\n\n\n\n<li>Voltage rating is a separate limit from power, and on small packages it usually binds first. A high-value 0402 can fail on voltage while dissipating a small fraction of its rated watts.<\/li>\n\n\n\n<li>Below 0603, package size stops being an electrical decision and becomes a process decision. It sets what your assembly house can place, inspect and rework.<\/li>\n\n\n\n<li>Use the largest package the layout allows. 0603 is the practical default: cheap, easy to inspect, and hand-reworkable.<\/li>\n<\/ul>\n<\/blockquote>\n\n\n\n<h2 class=\"wp-block-heading\">What Is an SMD Resistor?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">An SMD resistor is a fixed-value resistor in a leadless rectangular package, soldered to pads on the surface of a printed circuit board rather than through holes.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Four layers make up nearly every chip resistor. A ceramic substrate carries the part mechanically. A resistive film on top of it sets the resistance value. Metal terminations at each end make the electrical connection to the board. A protective overcoat seals the film against moisture and handling.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"380\" src=\"https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-chip-cross-section-1024x380.webp\" alt=\"Cross-section of a surface-mount chip resistor showing the protective overcoat, resistive film and ceramic substrate, with metal terminations wrapping both ends and solder fillets to the PCB pads\" class=\"wp-image-24207\" srcset=\"https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-chip-cross-section-1024x380.webp 1024w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-chip-cross-section-300x111.webp 300w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-chip-cross-section-768x285.webp 768w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-chip-cross-section-18x7.webp 18w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-chip-cross-section.webp 1400w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">The four layers of a chip resistor, with the terminations wrapping the body ends.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">SMD resistors displaced leaded parts for three practical reasons: no holes need drilling, both sides of the board become usable, and pick-and-place machines handle parts far smaller than a human can. The same package family covers capacitors, LEDs and diodes, which is why a board full of identical-looking rectangles is difficult to read by eye.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This guide is written for designers specifying parts, technicians identifying them, and engineers checking a BOM before a build.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How to Read SMD Resistor Codes<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Four marking systems cover practically every chip resistor, and the one that applies is decided by how many characters are printed on the body. Read the character count first, then apply the matching rule.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">The Three-Digit Code<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The first two digits are the significant figures and the third is the power-of-ten multiplier. A marking of <strong>103<\/strong> is 10 \u00d7 10\u00b3, or 10 k\u03a9. <strong>472<\/strong> is 47 \u00d7 10\u00b2, or 4.7 k\u03a9.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-left\" data-align=\"left\">Code<\/th><th class=\"has-text-align-left\" data-align=\"left\">Significant figures<\/th><th class=\"has-text-align-left\" data-align=\"left\">Multiplier<\/th><th class=\"has-text-align-left\" data-align=\"left\">Valeur<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-left\" data-align=\"left\">100<\/td><td class=\"has-text-align-left\" data-align=\"left\">10<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00d710\u2070<\/td><td class=\"has-text-align-left\" data-align=\"left\">10 \u03a9<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">220<\/td><td class=\"has-text-align-left\" data-align=\"left\">22<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00d710\u2070<\/td><td class=\"has-text-align-left\" data-align=\"left\">22 \u03a9<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">472<\/td><td class=\"has-text-align-left\" data-align=\"left\">47<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00d710\u00b2<\/td><td class=\"has-text-align-left\" data-align=\"left\">4.7 k\u03a9<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">103<\/td><td class=\"has-text-align-left\" data-align=\"left\">10<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00d710\u00b3<\/td><td class=\"has-text-align-left\" data-align=\"left\">10 k\u03a9<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">104<\/td><td class=\"has-text-align-left\" data-align=\"left\">10<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00d710\u2074<\/td><td class=\"has-text-align-left\" data-align=\"left\">100 k\u03a9<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">105<\/td><td class=\"has-text-align-left\" data-align=\"left\">10<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00d710\u2075<\/td><td class=\"has-text-align-left\" data-align=\"left\">1 M\u03a9<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">A three-digit code implies E24 values and typically \u00b15% or \u00b11% tolerance.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">The Four-Digit Code<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Three significant figures plus a multiplier, used on \u00b11% and tighter parts. <strong>1002<\/strong> is 100 \u00d7 10\u00b2, or 10 k\u03a9 \u2014 the same value as 103, expressed with more precision. <strong>4992<\/strong> is 499 \u00d7 10\u00b2, or 49.9 k\u03a9.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">The EIA-96 Code<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Two digits select a value from the 96-entry E96 table, and one letter sets the multiplier. This system is used on 1% parts where there is no room for four digits.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"344\" src=\"https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-code-decode-1024x344.webp\" alt=\"Four SMD chip packages showing the 103, 1002, 01C and 4R7 markings, each with the decoding rule, the arithmetic and the resulting resistance value\" class=\"wp-image-24208\" srcset=\"https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-code-decode-1024x344.webp 1024w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-code-decode-300x101.webp 300w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-code-decode-768x258.webp 768w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-code-decode-18x6.webp 18w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-code-decode.webp 1400w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">The four marking systems, each decoded to its value.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The multiplier letters, which two independent references give identically (<a href=\"https:\/\/eepower.com\/resistor-guide\/resistor-standards-and-codes\/resistor-smd-code\/\">EEPower, <em>Code SMD des r\u00e9sistances<\/em><\/a>; <a href=\"https:\/\/learn.sparkfun.com\/tutorials\/resistors\/decoding-resistor-markings\">SparkFun, <em>D\u00e9codage des marquages des r\u00e9sistances<\/em><\/a>, tous deux consult\u00e9s le 2026-10-21) :<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-left\" data-align=\"left\">Lettre<\/th><th class=\"has-text-align-left\" data-align=\"left\">Multiplier<\/th><th class=\"has-text-align-left\" data-align=\"left\">Lettre<\/th><th class=\"has-text-align-left\" data-align=\"left\">Multiplier<\/th><th class=\"has-text-align-left\" data-align=\"left\">Lettre<\/th><th class=\"has-text-align-left\" data-align=\"left\">Multiplier<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-left\" data-align=\"left\">Z<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.001<\/td><td class=\"has-text-align-left\" data-align=\"left\">A<\/td><td class=\"has-text-align-left\" data-align=\"left\">1<\/td><td class=\"has-text-align-left\" data-align=\"left\">D<\/td><td class=\"has-text-align-left\" data-align=\"left\">1,000<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">Y ou R<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.01<\/td><td class=\"has-text-align-left\" data-align=\"left\">B ou H<\/td><td class=\"has-text-align-left\" data-align=\"left\">10<\/td><td class=\"has-text-align-left\" data-align=\"left\">E<\/td><td class=\"has-text-align-left\" data-align=\"left\">10,000<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">X ou S<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.1<\/td><td class=\"has-text-align-left\" data-align=\"left\">C<\/td><td class=\"has-text-align-left\" data-align=\"left\">100<\/td><td class=\"has-text-align-left\" data-align=\"left\">F<\/td><td class=\"has-text-align-left\" data-align=\"left\">100,000<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Deux exemples d\u00e9taill\u00e9s : <strong>01C<\/strong> correspond au code 01 = 100, avec le multiplicateur C = 100, ce qui donne 10 k\u03a9. <strong>92Z<\/strong> correspond au code 92 = 887, avec le multiplicateur Z = 0,001, ce qui donne 0,887 \u03a9.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Les 96 codes et les valeurs auxquelles ils renvoient, issus du tableau des s\u00e9ries normalis\u00e9es de la norme IEC 60063 (<a href=\"https:\/\/www.vishay.com\/doc?28372\">Vishay, <em>Valeurs des s\u00e9ries normalis\u00e9es par d\u00e9cade pour les r\u00e9sistances et les condensateurs, de E3 \u00e0 E192 selon la norme IEC 60063<\/em>, document 28372<\/a>, consult\u00e9 le 2026-10-21) :<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-left\" data-align=\"left\">Code \u2192 valeur<\/th><th class=\"has-text-align-left\" data-align=\"left\">Code \u2192 valeur<\/th><th class=\"has-text-align-left\" data-align=\"left\">Code \u2192 valeur<\/th><th class=\"has-text-align-left\" data-align=\"left\">Code \u2192 valeur<\/th><th class=\"has-text-align-left\" data-align=\"left\">Code \u2192 valeur<\/th><th class=\"has-text-align-left\" data-align=\"left\">Code \u2192 valeur<\/th><th class=\"has-text-align-left\" data-align=\"left\">Code \u2192 valeur<\/th><th class=\"has-text-align-left\" data-align=\"left\">Code \u2192 valeur<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-left\" data-align=\"left\">01 \u2192 100<\/td><td class=\"has-text-align-left\" data-align=\"left\">02 \u2192 102<\/td><td class=\"has-text-align-left\" data-align=\"left\">03 \u2192 105<\/td><td class=\"has-text-align-left\" data-align=\"left\">04 \u2192 107<\/td><td class=\"has-text-align-left\" data-align=\"left\">05 \u2192 110<\/td><td class=\"has-text-align-left\" data-align=\"left\">06 \u2192 113<\/td><td class=\"has-text-align-left\" data-align=\"left\">07 \u2192 115<\/td><td class=\"has-text-align-left\" data-align=\"left\">08 \u2192 118<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">09 \u2192 121<\/td><td class=\"has-text-align-left\" data-align=\"left\">10 \u2192 124<\/td><td class=\"has-text-align-left\" data-align=\"left\">11 \u2192 127<\/td><td class=\"has-text-align-left\" data-align=\"left\">12 \u2192 130<\/td><td class=\"has-text-align-left\" data-align=\"left\">13 \u2192 133<\/td><td class=\"has-text-align-left\" data-align=\"left\">14 \u2192 137<\/td><td class=\"has-text-align-left\" data-align=\"left\">15 \u2192 140<\/td><td class=\"has-text-align-left\" data-align=\"left\">16 \u2192 143<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">17 \u2192 147<\/td><td class=\"has-text-align-left\" data-align=\"left\">18 \u2192 150<\/td><td class=\"has-text-align-left\" data-align=\"left\">19 \u2192 154<\/td><td class=\"has-text-align-left\" data-align=\"left\">20 \u2192 158<\/td><td class=\"has-text-align-left\" data-align=\"left\">21 \u2192 162<\/td><td class=\"has-text-align-left\" data-align=\"left\">22 \u2192 165<\/td><td class=\"has-text-align-left\" data-align=\"left\">23 \u2192 169<\/td><td class=\"has-text-align-left\" data-align=\"left\">24 \u2192 174<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">25 \u2192 178<\/td><td class=\"has-text-align-left\" data-align=\"left\">26 \u2192 182<\/td><td class=\"has-text-align-left\" data-align=\"left\">27 \u2192 187<\/td><td class=\"has-text-align-left\" data-align=\"left\">28 \u2192 191<\/td><td class=\"has-text-align-left\" data-align=\"left\">29 \u2192 196<\/td><td class=\"has-text-align-left\" data-align=\"left\">30 \u2192 200<\/td><td class=\"has-text-align-left\" data-align=\"left\">31 \u2192 205<\/td><td class=\"has-text-align-left\" data-align=\"left\">32 \u2192 210<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">33 \u2192 215<\/td><td class=\"has-text-align-left\" data-align=\"left\">34 \u2192 221<\/td><td class=\"has-text-align-left\" data-align=\"left\">35 \u2192 226<\/td><td class=\"has-text-align-left\" data-align=\"left\">36 \u2192 232<\/td><td class=\"has-text-align-left\" data-align=\"left\">37 \u2192 237<\/td><td class=\"has-text-align-left\" data-align=\"left\">38 \u2192 243<\/td><td class=\"has-text-align-left\" data-align=\"left\">39 \u2192 249<\/td><td class=\"has-text-align-left\" data-align=\"left\">40 \u2192 255<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">41 \u2192 261<\/td><td class=\"has-text-align-left\" data-align=\"left\">42 \u2192 267<\/td><td class=\"has-text-align-left\" data-align=\"left\">43 \u2192 274<\/td><td class=\"has-text-align-left\" data-align=\"left\">44 \u2192 280<\/td><td class=\"has-text-align-left\" data-align=\"left\">45 \u2192 287<\/td><td class=\"has-text-align-left\" data-align=\"left\">46 \u2192 294<\/td><td class=\"has-text-align-left\" data-align=\"left\">47 \u2192 301<\/td><td class=\"has-text-align-left\" data-align=\"left\">48 \u2192 309<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">49 \u2192 316<\/td><td class=\"has-text-align-left\" data-align=\"left\">50 \u2192 324<\/td><td class=\"has-text-align-left\" data-align=\"left\">51 \u2192 332<\/td><td class=\"has-text-align-left\" data-align=\"left\">52 \u2192 340<\/td><td class=\"has-text-align-left\" data-align=\"left\">53 \u2192 348<\/td><td class=\"has-text-align-left\" data-align=\"left\">54 \u2192 357<\/td><td class=\"has-text-align-left\" data-align=\"left\">55 \u2192 365<\/td><td class=\"has-text-align-left\" data-align=\"left\">56 \u2192 374<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">57 \u2192 383<\/td><td class=\"has-text-align-left\" data-align=\"left\">58 \u2192 392<\/td><td class=\"has-text-align-left\" data-align=\"left\">59 \u2192 402<\/td><td class=\"has-text-align-left\" data-align=\"left\">60 \u2192 412<\/td><td class=\"has-text-align-left\" data-align=\"left\">61 \u2192 422<\/td><td class=\"has-text-align-left\" data-align=\"left\">62 \u2192 432<\/td><td class=\"has-text-align-left\" data-align=\"left\">63 \u2192 442<\/td><td class=\"has-text-align-left\" data-align=\"left\">64 \u2192 453<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">65 \u2192 464<\/td><td class=\"has-text-align-left\" data-align=\"left\">66 \u2192 475<\/td><td class=\"has-text-align-left\" data-align=\"left\">67 \u2192 487<\/td><td class=\"has-text-align-left\" data-align=\"left\">68 \u2192 499<\/td><td class=\"has-text-align-left\" data-align=\"left\">69 \u2192 511<\/td><td class=\"has-text-align-left\" data-align=\"left\">70 \u2192 523<\/td><td class=\"has-text-align-left\" data-align=\"left\">71 \u2192 536<\/td><td class=\"has-text-align-left\" data-align=\"left\">72 \u2192 549<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">73 \u2192 562<\/td><td class=\"has-text-align-left\" data-align=\"left\">74 \u2192 576<\/td><td class=\"has-text-align-left\" data-align=\"left\">75 \u2192 590<\/td><td class=\"has-text-align-left\" data-align=\"left\">76 \u2192 604<\/td><td class=\"has-text-align-left\" data-align=\"left\">77 \u2192 619<\/td><td class=\"has-text-align-left\" data-align=\"left\">78 \u2192 634<\/td><td class=\"has-text-align-left\" data-align=\"left\">79 \u2192 649<\/td><td class=\"has-text-align-left\" data-align=\"left\">80 \u2192 665<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">81 \u2192 681<\/td><td class=\"has-text-align-left\" data-align=\"left\">82 \u2192 698<\/td><td class=\"has-text-align-left\" data-align=\"left\">83 \u2192 715<\/td><td class=\"has-text-align-left\" data-align=\"left\">84 \u2192 732<\/td><td class=\"has-text-align-left\" data-align=\"left\">85 \u2192 750<\/td><td class=\"has-text-align-left\" data-align=\"left\">86 \u2192 768<\/td><td class=\"has-text-align-left\" data-align=\"left\">87 \u2192 787<\/td><td class=\"has-text-align-left\" data-align=\"left\">88 \u2192 806<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">89 \u2192 825<\/td><td class=\"has-text-align-left\" data-align=\"left\">90 \u2192 845<\/td><td class=\"has-text-align-left\" data-align=\"left\">91 \u2192 866<\/td><td class=\"has-text-align-left\" data-align=\"left\">92 \u2192 887<\/td><td class=\"has-text-align-left\" data-align=\"left\">93 \u2192 909<\/td><td class=\"has-text-align-left\" data-align=\"left\">94 \u2192 931<\/td><td class=\"has-text-align-left\" data-align=\"left\">95 \u2192 953<\/td><td class=\"has-text-align-left\" data-align=\"left\">96 \u2192 976<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Notez que R appara\u00eet dans ce syst\u00e8me et dans le syst\u00e8me \u00e0 virgule d\u00e9cimale ci-dessous ; un marquage contenant R n\u2019est donc pas automatiquement un code EIA-96.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Le point d\u00e9cimal &#8220;R&#8221; et les lettres de tol\u00e9rance<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Pour les valeurs inf\u00e9rieures \u00e0 10 \u03a9, R indique la position de la virgule d\u00e9cimale : <strong>4R7<\/strong> correspond \u00e0 4,7 \u03a9, <strong>0R5<\/strong> correspond \u00e0 0,5 \u03a9, <strong>0R01<\/strong> correspond \u00e0 0,01 \u03a9.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Il convient de corriger explicitement un point, car il est enseign\u00e9 \u00e0 l\u2019envers sur certains sites consacr\u00e9s aux composants : sur une r\u00e9sistance CMS, une lettre finale est un code de tol\u00e9rance, et non un multiplicateur. Dans un marquage tel que <strong>103K<\/strong>, la valeur provient uniquement des chiffres \u2014 103 correspond \u00e0 10 k\u03a9 \u2014 et K indique une tol\u00e9rance de \u00b110 %. La lettre fournit une information suppl\u00e9mentaire sur le composant ; elle ne modifie pas le calcul.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Les conventions de marquage ne sont pas enti\u00e8rement normalis\u00e9es. Le guide d\u2019EEPower l\u2019indique directement, en pr\u00e9cisant qu\u2019un fabricant peut utiliser une variante ou quelque chose de compl\u00e8tement diff\u00e9rent ; la fiche technique pr\u00e9vaut donc sur tout tableau.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Tailles des r\u00e9sistances CMS et codes de bo\u00eetier<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Le code \u00e0 quatre chiffres correspond \u00e0 l\u2019empreinte en centi\u00e8mes de pouce, et non \u00e0 une puissance nominale.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Les colonnes de puissance et de tension ci-dessous concernent la <a href=\"https:\/\/www.yageo.com\/en\/Product\/Resistors\/Chip-Resistors\/Thick-Film-Resistors\/General-Purpose\/RC-Series\">s\u00e9rie Yageo RC<\/a>, une gamme \u00e0 couche \u00e9paisse \u00e0 usage g\u00e9n\u00e9ral (consult\u00e9e le 2026-10-21) ; les autres s\u00e9ries et fabricants diff\u00e8rent, parfois consid\u00e9rablement \u2014 la s\u00e9rie CRCW e3 de Vishay indique 400 V et 500 V pour ses formats 2010 et 2512, soit bien plus que les 200 V indiqu\u00e9s ici.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-left\" data-align=\"left\">imp\u00e9rial<\/th><th class=\"has-text-align-left\" data-align=\"left\">m\u00e9trique<\/th><th class=\"has-text-align-left\" data-align=\"left\">Taille (po)<\/th><th class=\"has-text-align-left\" data-align=\"left\">Taille (mm)<\/th><th class=\"has-text-align-left\" data-align=\"left\">Puissance typique<\/th><th class=\"has-text-align-left\" data-align=\"left\">Tension maximale typique<\/th><th class=\"has-text-align-left\" data-align=\"left\">Utilisation typique<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-left\" data-align=\"left\">01005<\/td><td class=\"has-text-align-left\" data-align=\"left\">0402<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.016 \u00d7 0.008<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.4 \u00d7 0.2<\/td><td class=\"has-text-align-left\" data-align=\"left\">1\/32 W<\/td><td class=\"has-text-align-left\" data-align=\"left\">15 V<\/td><td class=\"has-text-align-left\" data-align=\"left\">Objets connect\u00e9s, SiP<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">0201<\/td><td class=\"has-text-align-left\" data-align=\"left\">0603<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.024 \u00d7 0.012<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.6 \u00d7 0.3<\/td><td class=\"has-text-align-left\" data-align=\"left\">1\/20 W<\/td><td class=\"has-text-align-left\" data-align=\"left\">15\u201325 V<\/td><td class=\"has-text-align-left\" data-align=\"left\">Smartphones<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">0402<\/td><td class=\"has-text-align-left\" data-align=\"left\">1005<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.040 \u00d7 0.020<\/td><td class=\"has-text-align-left\" data-align=\"left\">1.0 \u00d7 0.5<\/td><td class=\"has-text-align-left\" data-align=\"left\">1\/16 W<\/td><td class=\"has-text-align-left\" data-align=\"left\">50 V<\/td><td class=\"has-text-align-left\" data-align=\"left\">Cartes haute densit\u00e9<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">0603<\/td><td class=\"has-text-align-left\" data-align=\"left\">1608<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.060 \u00d7 0.030<\/td><td class=\"has-text-align-left\" data-align=\"left\">1.6 \u00d7 0.8<\/td><td class=\"has-text-align-left\" data-align=\"left\">1\/10 W<\/td><td class=\"has-text-align-left\" data-align=\"left\">50\u201375 V<\/td><td class=\"has-text-align-left\" data-align=\"left\">Usage g\u00e9n\u00e9ral<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">0805<\/td><td class=\"has-text-align-left\" data-align=\"left\">2012<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.080 \u00d7 0.050<\/td><td class=\"has-text-align-left\" data-align=\"left\">2.0 \u00d7 1.25<\/td><td class=\"has-text-align-left\" data-align=\"left\">1\/8 W<\/td><td class=\"has-text-align-left\" data-align=\"left\">100\u2013150 V<\/td><td class=\"has-text-align-left\" data-align=\"left\">Adapt\u00e9 \u00e0 l\u2019assemblage manuel<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">1206<\/td><td class=\"has-text-align-left\" data-align=\"left\">3216<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.120 \u00d7 0.060<\/td><td class=\"has-text-align-left\" data-align=\"left\">3.2 \u00d7 1.6<\/td><td class=\"has-text-align-left\" data-align=\"left\">1\/4 W<\/td><td class=\"has-text-align-left\" data-align=\"left\">200 V<\/td><td class=\"has-text-align-left\" data-align=\"left\">Dissipation sup\u00e9rieure<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">1210<\/td><td class=\"has-text-align-left\" data-align=\"left\">3225<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.120 \u00d7 0.100<\/td><td class=\"has-text-align-left\" data-align=\"left\">3.2 \u00d7 2.5<\/td><td class=\"has-text-align-left\" data-align=\"left\">1\/2 W<\/td><td class=\"has-text-align-left\" data-align=\"left\">200 V<\/td><td class=\"has-text-align-left\" data-align=\"left\">Chemins de puissance<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">2010<\/td><td class=\"has-text-align-left\" data-align=\"left\">5025<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.200 \u00d7 0.100<\/td><td class=\"has-text-align-left\" data-align=\"left\">5.0 \u00d7 2.5<\/td><td class=\"has-text-align-left\" data-align=\"left\">3\/4 W<\/td><td class=\"has-text-align-left\" data-align=\"left\">200 V<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00c9lectronique de puissance<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">2512<\/td><td class=\"has-text-align-left\" data-align=\"left\">6332<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.250 \u00d7 0.120<\/td><td class=\"has-text-align-left\" data-align=\"left\">6.3 \u00d7 3.2<\/td><td class=\"has-text-align-left\" data-align=\"left\">1 W<\/td><td class=\"has-text-align-left\" data-align=\"left\">200 V<\/td><td class=\"has-text-align-left\" data-align=\"left\">Puissance, mesure du courant<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Pourquoi les dimensions publi\u00e9es diff\u00e8rent.<\/strong> Le code imp\u00e9rial est nominal en pouces et le code m\u00e9trique est nominal en millim\u00e8tres, et les deux ne correspondent pas exactement. Un 0603 mesure 0.060 \u00d7 0.030 po, soit 1.52 \u00d7 0.76 mm, tandis que son \u00e9quivalent m\u00e9trique 1608 mesure 1.6 \u00d7 0.8 mm. Les dimensions publi\u00e9es tiennent \u00e9galement compte d\u2019une tol\u00e9rance de fabrication. Deux fiches techniques peuvent \u00eatre toutes deux exactes tout en indiquant des valeurs diff\u00e9rentes pour le m\u00eame bo\u00eetier, c\u2019est pourquoi la fiche technique du MCT 0603 \u00e0 couche mince de Vishay indique un corps de 1.55 \u00d7 0.85 mm (<a href=\"https:\/\/www.vishay.com\/docs\/28700\/mcx0x0xpre.pdf\">Vishay, document 28700<\/a>, consult\u00e9 le 21\/10\/2026), tandis que son propre document CRCW e3 \u00e0 couche \u00e9paisse utilise 1.6 \u00d7 0.8 mm.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Pourquoi les puissances nominales diff\u00e8rent, et pourquoi cela est plus important.<\/strong> La puissance nominale d\u00e9pend de la s\u00e9rie, de la technologie de la couche et du fabricant \u2014 pas du code du bo\u00eetier. Un composant 1206 \u00e0 couche \u00e9paisse d\u2019usage g\u00e9n\u00e9ral est g\u00e9n\u00e9ralement donn\u00e9 pour 1\/4 W, tandis qu\u2019un 1206 d\u2019une s\u00e9rie haute puissance peut \u00eatre donn\u00e9 pour 1\/2 W. Consid\u00e9rer le code du bo\u00eetier comme une puissance nominale est pr\u00e9cis\u00e9ment l\u2019erreur que cette section vise \u00e0 pr\u00e9venir, et cela m\u00e8ne directement \u00e0 la suivante.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Puissance nominale et d\u00e9classement thermique<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">La puissance nominale publi\u00e9e d\u2019une r\u00e9sistance \u00e0 puce n\u2019est pas la puissance qu\u2019elle peut dissiper dans votre produit. Il s\u2019agit de la puissance qu\u2019elle peut dissiper \u00e0 une temp\u00e9rature ambiante donn\u00e9e, et cette valeur diminue jusqu\u2019\u00e0 z\u00e9ro avant que le composant n\u2019atteigne sa temp\u00e9rature maximale de cat\u00e9gorie.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">La fiche technique de la r\u00e9sistance \u00e0 puce de pr\u00e9cision \u00e0 couche \u00e9paisse de Vishay d\u00e9finit <strong>la dissipation nominale P\u2087\u2080<\/strong> comme la charge maximale autoris\u00e9e \u00e0 une temp\u00e9rature ambiante de 70 \u00b0C, et indique directement les limites du d\u00e9classement : 100 % de la puissance nominale \u00e0 70 \u00b0C, diminuant lin\u00e9airement jusqu\u2019\u00e0 0 % \u00e0 155 \u00b0C (<a href=\"https:\/\/www.vishay.com\/docs\/20035\/dcrcwe3.pdf\">Vishay, <em>R\u00e9sistances \u00e0 puce standard \u00e0 couche \u00e9paisse D\/CRCW e3<\/em>, document 20035<\/a>, consult\u00e9 le 21\/10\/2026). Le m\u00eame document sp\u00e9cifie une temp\u00e9rature de couche admissible de 155 \u00b0C et cite la norme EN 60115-1 comme sp\u00e9cification g\u00e9n\u00e9rique applicable \u00e0 ses proc\u00e9dures d\u2019essai.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Cette r\u00e8gle lin\u00e9aire constitue l\u2019int\u00e9gralit\u00e9 du calcul. Entre 70 \u00b0C et 155 \u00b0C, la puissance utilisable est :<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\">fraction utilisable = (155 \u2212 temp\u00e9rature ambiante) \u00f7 85<\/p>\n<\/blockquote>\n\n\n\n<p class=\"wp-block-paragraph\">Ainsi, \u00e0 100 \u00b0C, un composant conserve (155 \u2212 100) \u00f7 85 \u2248 <strong>65%<\/strong> de sa puissance nominale. \u00c0 125 \u00b0C, il en conserve environ <strong>35%<\/strong>. En dessous de 70 \u00b0C, la puissance nominale n\u2019est g\u00e9n\u00e9ralement pas augment\u00e9e.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"478\" src=\"https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/chart-derating-1024x478.webp\" alt=\"Line chart of chip resistor power derating: usable power holds at 100 percent up to 70 degrees C, then falls linearly to zero at 155 degrees C, with the 100 and 125 degree operating points marked at 65 and 35 percent\" class=\"wp-image-24209\" srcset=\"https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/chart-derating-1024x478.webp 1024w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/chart-derating-300x140.webp 300w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/chart-derating-768x358.webp 768w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/chart-derating-18x8.webp 18w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/chart-derating.webp 1200w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">La dissipation nominale reste valable jusqu\u2019\u00e0 70 \u00b0C, puis diminue lin\u00e9airement jusqu\u2019\u00e0 z\u00e9ro \u00e0 la temp\u00e9rature maximale de cat\u00e9gorie. Source : fiche technique de la r\u00e9sistance \u00e0 puce de pr\u00e9cision \u00e0 couche \u00e9paisse de Vishay.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Exemple de calcul.<\/strong> Une r\u00e9sistance 0603 donn\u00e9e pour 0.1 W se trouve dans un bo\u00eetier qui atteint 100 \u00b0C. La puissance disponible est de 0.1 W \u00d7 0.65 = <strong>65 mW<\/strong>. Le circuit fait circuler 9 mA dans une r\u00e9sistance de 1 k\u03a9 : P = I\u00b2R = 0.009\u00b2 \u00d7 1 000 = <strong>81 mW<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The part fails \u2014 and this is the trap: at 70 \u00b0C the same 81 mW would have sat comfortably inside the 100 mW rating. The part passes on the bench and fails in the enclosure.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Why small packages are hit hardest.<\/strong> Power density rises as the body shrinks, and there is less pad copper to sink heat into. The pad and its copper are part of the thermal path, which is why the land pattern in the next section is also a thermal decision, not only a mechanical one.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Mitigations,<\/strong> in the order worth trying: move up a package size, widen the pads and the copper connecting to them, add thermal vias where the layout allows, or split the dissipation across two parts in series or parallel.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Land Patterns and Pad Geometry<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The pad dimensions decide whether the part solders reliably, and they are not the same as the component dimensions.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The pad is deliberately larger than the termination. That extra copper gives solder somewhere to wet, and it gives the part self-alignment: surface tension in the molten solder pulls a slightly misplaced chip into position during reflow.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Three dimensions govern the result. <strong>Pad width<\/strong> sets joint strength. <strong>Pad length<\/strong> \u2014 the extension beyond the termination \u2014 sets the fillet and the self-alignment force. <strong>The gap between the two pads<\/strong> sets bridging risk and decides how much solder sits between the terminations.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">IPC-7351 defines three density levels. <strong>Level A<\/strong> gives the most land protrusion and the widest process window, and suits low-density boards and wave soldering. <strong>Level B<\/strong> is the nominal default and is what most production boards use. <strong>Level C<\/strong> gives the least protrusion for high-density designs, and IPC-7351 calls for user qualification before adopting it.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Vishay&#8217;s land pattern document states that its figures reflect IPC-7351 and IEC 61188-6-2, and it publishes a set for each (<a href=\"https:\/\/www.vishay.com\/doc?28950\">Vishay, recommended solder pad dimensions for surface-mount resistors and fuses, document 28950<\/a>, retrieved 2026-10-21). In both, <strong>C is the gap between the two pads, Y is the pad length along the component axis and X is the pad width across it<\/strong>, so the overall footprint is Z = C + 2Y:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-left\" data-align=\"left\">Bo\u00eetier<\/th><th class=\"has-text-align-left\" data-align=\"left\">IPC-7351, reflow (C, Y, X, Z)<\/th><th class=\"has-text-align-left\" data-align=\"left\">IEC 61188-6-2, reflow (C, Y, X, Z)<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-left\" data-align=\"left\">0201<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.27, 0.43, 0.42, 1.13<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.30, 0.24, 0.32, 0.78<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">0402<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.40, 0.55, 0.60, 1.50<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.55, 0.35, 0.55, 1.25<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">0603<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.70, 0.90, 1.00, 2.50<\/td><td class=\"has-text-align-left\" data-align=\"left\">0.90, 0.55, 0.90, 2.00<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">0805<\/td><td class=\"has-text-align-left\" data-align=\"left\">1.00, 0.90, 1.45, 2.80<\/td><td class=\"has-text-align-left\" data-align=\"left\">1.10, 0.65, 1.30, 2.40<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">1206<\/td><td class=\"has-text-align-left\" data-align=\"left\">1.75, 1.15, 1.80, 4.05<\/td><td class=\"has-text-align-left\" data-align=\"left\">2.10, 0.80, 1.65, 3.70<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">1210<\/td><td class=\"has-text-align-left\" data-align=\"left\">1.75, 1.15, 2.65, 4.05<\/td><td class=\"has-text-align-left\" data-align=\"left\">2.10, 0.80, 2.50, 3.70<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Read the 0603 row as two pads 1.00 mm wide and 0.90 mm long, separated by a 0.70 mm gap, giving a 2.50 mm overall footprint. The overall dimension is the useful check: the pad must be wider than the body it carries and the footprint longer than the part, which is why Z = C + 2Y holds on every row above.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The IEC set is consistently tighter \u2014 a smaller pad on a wider gap \u2014 and the two standards are not interchangeable. IPC-7351&#8217;s three density levels adjust these further; the table above is the nominal reflow set for Vishay&#8217;s thin-film chip parts, and a different series or vendor will publish different numbers.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"410\" src=\"https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-land-pattern-1024x410.webp\" alt=\"Dimensioned land pattern for a 0603 chip resistor showing the pad gap C, pad length Y along the component axis and pad width X across it, with the pad extension beyond the termination marked and the component body drawn over the pads\" class=\"wp-image-24210\" srcset=\"https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-land-pattern-1024x410.webp 1024w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-land-pattern-300x120.webp 300w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-land-pattern-768x307.webp 768w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-land-pattern-18x7.webp 18w, https:\/\/lead-pcb.com\/wp-content\/uploads\/2026\/10\/diagram-land-pattern.webp 1400w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">IPC-7351 reflow land pattern for a 0603, in millimetres.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Two further points belong here. Pads are defined as solder-mask-defined or non-solder-mask-defined, and the stencil aperture is usually reduced from the pad to control paste volume. And unequal copper on the two pads of a small chip means unequal heating, which is the primary mechanism behind tombstoning \u2014 picked up again in the assembly section.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Voltage Rating and Other Limits<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A chip resistor carries two independent limits \u2014 a power limit and a voltage limit \u2014 and on small packages the voltage limit usually binds first.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Power rating is a thermal property. Voltage rating is a dielectric property, set by the body length and the spacing between terminations. They are physically unrelated, and both must be satisfied.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The crossover is where the binding constraint flips. A resistor reaches its rated voltage at V = \u221a(P \u00d7 R), so the critical resistance where voltage takes over from power is R = V\u00b2 \u00f7 P. For a 0402 rated 50 V and 1\/16 W, that is 50\u00b2 \u00f7 0.0625 = <strong>40 k\u03a9<\/strong>. Above 40 k\u03a9 the part is voltage-limited and can break down while dissipating a small fraction of its rated watts. For a 0603 rated 75 V and 0.1 W the crossover is about 56 k\u03a9, and for a 1206 rated 200 V and 1\/4 W it is about 160 k\u03a9.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Typical maximum working voltages for general-purpose thick-film series run roughly 50 V for 0402, 50\u201375 V for 0603 and 100\u2013150 V for 0805. From 1206 upward they sit at 200 V (<a href=\"https:\/\/www.yageo.com\/en\/Product\/Resistors\/Chip-Resistors\/Thick-Film-Resistors\/General-Purpose\/RC-Series\">Yageo, <em>RC series general-purpose thick film chip resistors<\/em><\/a>, retrieved 2026-10-21). Two caveats matter: voltage does not keep rising with size \u2014 Yageo&#8217;s RC series holds 200 V from 1206 all the way to 2512 \u2014 and there is real brand-to-brand spread, with Vishay&#8217;s CRCW e3 rating its 2010 and 2512 at 400 V and 500 V and some vendors rating 0402 at 25 V rather than 50 V. Check the exact series.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Two more boundaries are worth knowing. Short-term overload voltage is a separate and higher specification; Vishay&#8217;s CRCW-HP e3 datasheet, for example, rates its parts for a pulse load well above the continuous operating voltage (<a href=\"https:\/\/www.vishay.com\/docs\/20043\/crcwhpe3.pdf\">Vishay, document 20043<\/a>, retrieved 2026-10-21). And pulse handling differs from continuous rating: standard thick film handles pulses relatively poorly, which is why anti-surge and pulse-withstanding series exist.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Tolerance, TCR and Value Series<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Tolerance tells you how far a part can sit from its marked value the moment you buy it. TCR tells you how far it will move afterwards. They are different specifications, bought separately.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-left\" data-align=\"left\">Tol\u00e9rance<\/th><th class=\"has-text-align-left\" data-align=\"left\">Typical film technology<\/th><th class=\"has-text-align-left\" data-align=\"left\">Utilisation typique<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-left\" data-align=\"left\">\u00b15%<\/td><td class=\"has-text-align-left\" data-align=\"left\">Thick film<\/td><td class=\"has-text-align-left\" data-align=\"left\">Applications de pull-up, limitation de courant pour LED, diviseurs non critiques<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u00b11 %<\/td><td class=\"has-text-align-left\" data-align=\"left\">Film \u00e9pais ou mince<\/td><td class=\"has-text-align-left\" data-align=\"left\">Pr\u00e9cision g\u00e9n\u00e9rale, r\u00e9seaux de r\u00e9troaction<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u00b10,5 %<\/td><td class=\"has-text-align-left\" data-align=\"left\">Film mince<\/td><td class=\"has-text-align-left\" data-align=\"left\">Diviseurs de pr\u00e9cision, r\u00e9f\u00e9rences<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u00b10,1 % et plus pr\u00e9cis<\/td><td class=\"has-text-align-left\" data-align=\"left\">Film mince, feuille m\u00e9tallique<\/td><td class=\"has-text-align-left\" data-align=\"left\">Instrumentation, \u00e9talonnage<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Le lien avec les s\u00e9ries E est l\u2019aspect que la plupart des guides omettent : les valeurs que vous pouvez r\u00e9ellement acheter d\u00e9pendent de la tol\u00e9rance. E24 correspond \u00e0 \u00b15 % et E48 \u00e0 \u00b12 %. E96 correspond \u00e0 \u00b11 %, et E192 \u00e0 \u00b10,5 % et plus pr\u00e9cis (<a href=\"https:\/\/www.vishay.com\/doc?28372\">Vishay, <em>Valeurs des s\u00e9ries normalis\u00e9es par d\u00e9cade pour les r\u00e9sistances et les condensateurs, de E3 \u00e0 E192 selon la norme IEC 60063<\/em>, document 28372<\/a>, consult\u00e9 le 21\/10\/2026). L\u2019espacement des valeurs au sein de chaque s\u00e9rie refl\u00e8te la tol\u00e9rance qu\u2019elle prend en charge. Ainsi, sp\u00e9cifier une valeur qui n\u2019appartient pas \u00e0 la s\u00e9rie E96 avec une tol\u00e9rance de \u00b11 % signifie choisir un composant non standard, avec un d\u00e9lai d\u2019approvisionnement plus long et un prix plus \u00e9lev\u00e9.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Le TCR, exprim\u00e9 en ppm\/\u00b0C, est le domaine o\u00f9 les films \u00e9pais et minces se diff\u00e9rencient le plus nettement. Un guide d\u2019achat consacr\u00e9 aux sp\u00e9cifications des r\u00e9sistances indique un film \u00e9pais \u00e0 environ \u00b1100 \u00e0 \u00b1200 ppm\/\u00b0C et un film mince \u00e0 environ \u00b15 \u00e0 \u00b125 ppm\/\u00b0C \u2014 soit pr\u00e8s d\u2019un ordre de grandeur (<a href=\"https:\/\/www.abacuselect.com\/resources\/resistor-types-specs-complete-buyers-guide\/\">Abacus Select, <em>Types et sp\u00e9cifications des r\u00e9sistances<\/em><\/a>, consult\u00e9 le 21\/10\/2026). Le TCR est important dans les diviseurs de pr\u00e9cision, les circuits de d\u00e9tection de courant et les circuits de r\u00e9f\u00e9rence. Il n\u2019a pas d\u2019importance pour une r\u00e9sistance de pull-up ou de limitation de courant pour LED.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">La tol\u00e9rance et la stabilit\u00e9 ne d\u00e9signent pas non plus la m\u00eame chose. La tol\u00e9rance est la pr\u00e9cision initiale au moment de l\u2019achat ; la stabilit\u00e9 \u00e0 long terme indique dans quelle mesure la valeur d\u00e9rive en service. Un composant \u00e0 tol\u00e9rance serr\u00e9e peut tout de m\u00eame d\u00e9river, et ces deux caract\u00e9ristiques sont sp\u00e9cifi\u00e9es s\u00e9par\u00e9ment dans la fiche technique.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Quels sont les diff\u00e9rents types de r\u00e9sistances CMS ?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Le type d\u00e9pend de la mani\u00e8re dont l\u2019\u00e9l\u00e9ment r\u00e9sistif est fabriqu\u00e9, et cette construction d\u00e9termine la pr\u00e9cision, le bruit et la tenue en puissance que vous pouvez obtenir \u2014 g\u00e9n\u00e9ralement pas les trois \u00e0 la fois.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Les colonnes relatives \u00e0 la tol\u00e9rance et au TCR pr\u00e9sentent des plages typiques relev\u00e9es dans les fiches techniques de plusieurs fabricants pour chaque construction, et non une norme unique ; les valeurs indiqu\u00e9es pour les films \u00e9pais et minces suivent les plages de <a href=\"https:\/\/www.abacuselect.com\/resources\/resistor-types-specs-complete-buyers-guide\/\">Abacus Select, <em>Types et sp\u00e9cifications des r\u00e9sistances<\/em><\/a>, consult\u00e9 le 21\/10\/2026.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-left\" data-align=\"left\">Type<\/th><th class=\"has-text-align-left\" data-align=\"left\">Construction<\/th><th class=\"has-text-align-left\" data-align=\"left\">Tol\u00e9rance typique<\/th><th class=\"has-text-align-left\" data-align=\"left\">TCR typique<\/th><th class=\"has-text-align-left\" data-align=\"left\">Utilisation typique<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-left\" data-align=\"left\">Thick film<\/td><td class=\"has-text-align-left\" data-align=\"left\">P\u00e2te r\u00e9sistive imprim\u00e9e sur de l\u2019alumine, cuite puis ajust\u00e9e au laser<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00b11 % \u00e0 \u00b15 %<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00b1100\u2013200 ppm\/\u00b0C<\/td><td class=\"has-text-align-left\" data-align=\"left\">Choix par d\u00e9faut pour presque toutes les applications<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">Film mince<\/td><td class=\"has-text-align-left\" data-align=\"left\">Film d\u00e9pos\u00e9 sous vide, photograv\u00e9 et ajust\u00e9 avec pr\u00e9cision<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00b10,05 % \u00e0 \u00b10,5 %<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00b15\u201325 ppm\/\u00b0C<\/td><td class=\"has-text-align-left\" data-align=\"left\">Pr\u00e9cision, faible bruit, instrumentation<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">Feuille m\u00e9tallique<\/td><td class=\"has-text-align-left\" data-align=\"left\">Feuille en alliage r\u00e9sistif sur un substrat<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00b10,01 % et plus pr\u00e9cis<\/td><td class=\"has-text-align-left\" data-align=\"left\">Jusqu\u2019\u00e0 \u00b11 ppm\/\u00b0C<\/td><td class=\"has-text-align-left\" data-align=\"left\">R\u00e9f\u00e9rences, d\u00e9tection de courant de pr\u00e9cision<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">Bobin\u00e9e \/ haute puissance<\/td><td class=\"has-text-align-left\" data-align=\"left\">Fil en alliage sur un noyau en c\u00e9ramique<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00b11 % \u00e0 \u00b15 %<\/td><td class=\"has-text-align-left\" data-align=\"left\">Faible<\/td><td class=\"has-text-align-left\" data-align=\"left\">Alimentations, commande de moteurs<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">D\u00e9tection de courant<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00c9l\u00e9ment m\u00e9tallique ou feuille m\u00e9tallique, tr\u00e8s faibles valeurs<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00b10,5 % \u00e0 \u00b11 %<\/td><td class=\"has-text-align-left\" data-align=\"left\">Faible<\/td><td class=\"has-text-align-left\" data-align=\"left\">Puissance, gestion de batterie<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">MELF<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00c9lectrode m\u00e9tallique cylindrique<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00b11 % \u00e0 \u00b15 %<\/td><td class=\"has-text-align-left\" data-align=\"left\">Faible<\/td><td class=\"has-text-align-left\" data-align=\"left\">Haute fiabilit\u00e9, fonctionnement en impulsions<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">R\u00e9seaux \/ ensembles<\/td><td class=\"has-text-align-left\" data-align=\"left\">Plusieurs r\u00e9sistances appari\u00e9es dans un m\u00eame bo\u00eetier<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00b11 % \u00e0 \u00b15 %<\/td><td class=\"has-text-align-left\" data-align=\"left\">Appari\u00e9es<\/td><td class=\"has-text-align-left\" data-align=\"left\">Bussed pull-ups, termination<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">Anti-surge \/ fusible<\/td><td class=\"has-text-align-left\" data-align=\"left\">Thick film tuned for pulse duty<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u00b15%<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u2014<\/td><td class=\"has-text-align-left\" data-align=\"left\">Input protection, fuse action<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Thick versus thin film is the decision a designer actually faces. Thick film is screen-printed resistive paste fired onto an alumina substrate and laser-trimmed to value; thin film is vacuum-deposited and photo-etched, which is why it costs more (<a href=\"https:\/\/jlcpcb.com\/hk\/blog\/thin-film-vs-thick-film-resistors\">JLCPCB, <em>Thin Film vs Thick Film Resistors<\/em><\/a>, retrieved 2026-10-21). The difference shows up as precision and temperature stability, bought at the cost of price and of power handling.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Thick film dominates for a reason: it is the cheapest, it covers the widest value range, and it is adequate for almost everything.<\/strong> For a pull-up, an LED limiter, or a divider feeding a comparator, thick film is correct and thin film is wasted money. Spend on thin film where the circuit actually measures something.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How to Identify an SMD Resistor With No Marking<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">En dessous du 0603, et pour de nombreux <a href=\"https:\/\/lead-pcb.com\/fr\/blog\/smd-resistor\/\" data-type=\"post\" data-id=\"24068\">composants 0402<\/a>, il n\u2019y a pas de place pour un code. Si le composant est vierge, sa valeur doit provenir de la documentation ou d\u2019une mesure \u2014 et une mesure en circuit peut \u00eatre trompeuse.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Read the reel label or the bag first<\/strong>, and trace it to the BOM line and the placement file. This is the only method that is certain, and it is the one people skip.<\/li>\n\n\n\n<li><strong>If the board came from a known design<\/strong>, find the designator and read the value from the schematic or BOM.<\/li>\n\n\n\n<li><strong>Measuring in circuit gives a wrong answer whenever a parallel path exists<\/strong> \u2014 another resistor, an IC input, an internal pull-up. The reading will be lower than the true value, sometimes dramatically. This is the mistake everyone makes first.<\/li>\n\n\n\n<li><strong>To measure a part in circuit, break the path<\/strong>: lift one termination with hot air or a second iron tip, then measure. On 0402 and below this is delicate work and risks losing the part.<\/li>\n\n\n\n<li><strong>Once removed, match the reading to the nearest E24 or E96 value.<\/strong> The measured value sits within tolerance of nominal, not on it \u2014 a 10 k\u03a9 \u00b15% part can legitimately read anywhere from 9.5 k\u03a9 to 10.5 k\u03a9.<\/li>\n\n\n\n<li><strong>When the part is damaged or open and no documentation exists, infer from circuit function<\/strong> \u2014 a pull-up, a divider ratio, a current-sense path. Say plainly that this is inference, not identification, and verify the result on a known-good board if one exists.<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">The last two steps are worth stating honestly because they carry real risk: an inferred value on a prototype is a hypothesis, and it should be treated as one until the design documentation confirms it.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How Package Size Affects Assembly and Yield<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Package size is not only an electrical decision. Below 0603 it becomes a process decision, and it changes what your assembly house can place, inspect and rework.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>0603 and 0805 are routine.<\/strong> The process window is wide, solder self-alignment works well, and stencil printing and vision recognition tolerate normal variation. These sizes are the safe default.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>0402 is the volume workhorse, and the point where the window tightens.<\/strong> Pad area drops sharply, so paste-volume tolerance becomes sensitive: slight stencil clogging or squeegee variation produces unequal solder on the two terminations. Lines running 0402 at volume need well-maintained nozzles and capable vision systems.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>0201 and 01005 need advanced equipment.<\/strong> Placement accuracy requirements tighten to roughly \u00b10.03 mm, tombstoning and misalignment rates rise, and the small mass means minor solder-volume variation or air turbulence can shift a part during placement. Not every line can build them, so the smallest package on a design sets the class of line it can be built on (<a href=\"https:\/\/jkrglo.com\/smd-resistor-package-sizes\/\">JK RG, <em>SMD Resistor Package Sizes<\/em><\/a>, retrieved 2026-10-21).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Effet tombstone<\/strong> is the defect that follows small chips. The part stands up on one end because one pad wets before the other. The causes are thermal asymmetry in the pad copper \u2014 especially one pad tied to a plane or a wide pour \u2014 unequal paste volume between the two pads, placement offset toward one side, and too steep a reflow ramp (<a href=\"https:\/\/www.aivon.com\/video\/pcb-basics\/pcb-tombstoning-causes-and-prevention-in-smt-assembly\">AIVON, <em>PCB Tombstoning: Causes and Prevention<\/em><\/a>, retrieved 2026-10-21). Symmetric pads with matched copper area are the primary fix, and it belongs at layout rather than at the oven.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Inspection has a floor.<\/strong> Marking follows the threshold above: 0603 and larger are usually printed, 0402 frequently is not, and below 0402 almost never is. Verification on small parts therefore has to come from the placement file and the BOM rather than from a camera. The consequence is worth stating: an unmarked small part cannot be verified by inspection, only by process control.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Rework gets harder.<\/strong> 0402 and below are hot-air work with preheat, and repeated rework on a small pad lifts copper.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>The practical rule: use the largest package the layout allows.<\/strong> 0603 is the sweet spot for most designs \u2014 hand-reworkable, cheap, easy to inspect, and small enough for dense layouts. Joint quality on those pads is ultimately judged against a named acceptance class, covered in our <a href=\"https:\/\/lead-pcb.com\/fr\/blog\/ipc-a-610\/\" data-type=\"post\" data-id=\"6767\">guide to IPC-A-610 acceptance criteria<\/a> for chip component solder joints.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Questions fr\u00e9quemment pos\u00e9es<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">What is the value of SMD resistor 1002?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/lead-pcb.com\/fr\/blog\/10k-resistor\/\" data-type=\"post\" data-id=\"23470\">10 k\u03a9<\/a>. Le code \u00e0 quatre chiffres donne trois chiffres significatifs (100) et un multiplicateur de 10\u00b2, donc 100 \u00d7 100 = 10 000 \u03a9.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">How do I find the value of an SMD resistor?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Read the code printed on the body and decode it \u2014 three digits, four digits, EIA-96, or an R decimal point, depending on how many characters are marked. If the part is unmarked, trace it through the BOM and placement file, or measure it out of circuit.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What are the different types of SMD resistors?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Film \u00e9pais, film mince, feuille m\u00e9tallique, bobin\u00e9 et haute puissance, \u00e0 d\u00e9tection de courant, MELF, r\u00e9seaux, ainsi que types anti-surtension ou fusibles \u2014 distingu\u00e9s par la mani\u00e8re dont l\u2019\u00e9l\u00e9ment r\u00e9sistif est fabriqu\u00e9. Le film \u00e9pais est le choix par d\u00e9faut ; le film mince est l\u2019option de pr\u00e9cision.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Comment identifier une r\u00e9sistance CMS non marqu\u00e9e ?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">La taille du bo\u00eetier, la couleur du corps et les marquages permettent de distinguer les r\u00e9sistances des condensateurs et des diodes, mais la mesure et la nomenclature sont les \u00e9l\u00e9ments qui le confirment. L\u2019identification visuelle seule n\u2019est pas fiable, en particulier pour les composants 0402 et plus petits, dont les marquages sont souvent absents.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Quelle est la diff\u00e9rence entre une r\u00e9sistance 0603 et une r\u00e9sistance 0805 ?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Le bo\u00eetier 0805 est plus grand \u2014 2,0 \u00d7 1,25 mm contre 1,6 \u00d7 0,8 mm \u2014 et pr\u00e9sente g\u00e9n\u00e9ralement une puissance et une tension nominales plus \u00e9lev\u00e9es. En pratique, la g\u00e9om\u00e9trie des pastilles, l\u2019inspection automatis\u00e9e et la retouche manuelle sont toutes facilit\u00e9es.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Puis-je utiliser une r\u00e9sistance CMS plus grande que celle sp\u00e9cifi\u00e9e ?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u00c9lectriquement, oui dans la plupart des cas. M\u00e9caniquement, cela d\u00e9pend de l\u2019espace disponible pour les pastilles et la zone d\u2019exclusion, et un bo\u00eetier plus grand ne peut que rarement \u00eatre pos\u00e9 sur la m\u00eame empreinte sans modifier le motif de pastilles.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Pourquoi ma r\u00e9sistance CMS chauffe-t-elle ?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Soit elle dissipe davantage que ce que sa puissance nominale autorise apr\u00e8s d\u00e9classement en fonction de la temp\u00e9rature ambiante, soit elle est sous-dimensionn\u00e9e par rapport au cuivre disponible pour \u00e9vacuer la chaleur. Un composant qui reste conforme \u00e0 70 \u00b0C peut chauffer \u00e0 100 \u00b0C avec le m\u00eame courant \u2014 consultez le calcul de d\u00e9classement ci-dessus.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Conclusion<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Le code du bo\u00eetier indique une empreinte, et non une puissance nominale. La puissance d\u00e9pend de la s\u00e9rie et du fabricant, et elle diminue avec la temp\u00e9rature ambiante \u2014 une r\u00e9sistance 0603 donn\u00e9e pour 0,1 W ne dispose plus que d\u2019environ 65 mW \u00e0 100 \u00b0C, ce qui explique un nombre \u00e9tonnant de d\u00e9faillances \u00ab cela fonctionnait sur l\u2019\u00e9tabli \u00bb.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">La tension constitue une deuxi\u00e8me limite ind\u00e9pendante et, pour les petits bo\u00eetiers, elle est atteinte avant la limite de puissance. En dessous du 0603, le choix cesse d\u2019\u00eatre \u00e9lectrique et devient une d\u00e9cision li\u00e9e au processus, qui d\u00e9termine ce qui peut \u00eatre plac\u00e9, inspect\u00e9 et retouch\u00e9. Les codes sont conventionnels plut\u00f4t qu\u2019universels : la fiche technique fait donc autorit\u00e9, avant tout tableau.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">L\u2019\u00e9tape pratique avant votre prochaine fabrication est simple. Prenez le plus petit bo\u00eetier et la marge de puissance la plus faible de votre nomenclature. V\u00e9rifiez-les tous deux par rapport \u00e0 la courbe de d\u00e9classement et au tableau des dimensions d\u2019empreinte. Notre \u00e9quipe examine le choix des composants et les empreintes dans le cadre d\u2019un devis d\u2019assemblage de circuits imprim\u00e9s ; cela vaut la peine de le faire avant la mise en panneau des cartes, et non apr\u00e8s.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Sources<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Vishay, <a href=\"https:\/\/www.vishay.com\/docs\/20035\/dcrcwe3.pdf\"><em>R\u00e9sistances \u00e0 puce standard \u00e0 couche \u00e9paisse D\/CRCW e3<\/em>, document 20035<\/a>, pour la dissipation nominale P\u2087\u2080, la courbe de d\u00e9classement de 70 \u00b0C \u00e0 155 \u00b0C, la temp\u00e9rature admissible du film de 155 \u00b0C, la plage de fonctionnement de \u221255 \u00b0C \u00e0 +155 \u00b0C et la r\u00e9f\u00e9rence d\u2019essai EN 60115-1. Consult\u00e9 le 21\/10\/2026.<\/li>\n\n\n\n<li>Vishay, <a href=\"https:\/\/www.vishay.com\/doc?28950\">dimensions recommand\u00e9es des pastilles de soudure pour les r\u00e9sistances et fusibles mont\u00e9s en surface, document 28950<\/a>, pour les valeurs d\u2019\u00e9cart, de longueur et de largeur des pastilles de refusion selon IPC-7351 et IEC 61188-6-2, pour les bo\u00eetiers 0201 \u00e0 1210, ainsi que pour la relation Z = C + 2Y utilis\u00e9e pour les v\u00e9rifier. Consult\u00e9 le 21\/10\/2026.<\/li>\n\n\n\n<li>Vishay, <a href=\"https:\/\/www.vishay.com\/docs\/20043\/crcwhpe3.pdf\"><em>R\u00e9sistances \u00e0 puce en film \u00e9pais, haute puissance, avec tenue aux impulsions CRCW-HP e3<\/em>, document 20043<\/a>, pour les valeurs de charge impulsionnelle et de surcharge de courte dur\u00e9e compar\u00e9es \u00e0 la tension de fonctionnement continue. Consult\u00e9 le 21\/10\/2026.<\/li>\n\n\n\n<li>Vishay, <a href=\"https:\/\/www.vishay.com\/docs\/28700\/mcx0x0xpre.pdf\"><em>R\u00e9sistances \u00e0 puce plates de pr\u00e9cision en film mince MCS 0402, MCT 0603, MCU 0805, MCA 1206<\/em>, document 28700<\/a>, pour la dimension de 1,55 \u00d7 0,85 mm du corps d\u2019une MCT 0603. Consult\u00e9 le 21\/10\/2026.<\/li>\n\n\n\n<li>EEPower, <a href=\"https:\/\/eepower.com\/resistor-guide\/resistor-standards-and-codes\/resistor-smd-code\/\">Code SMD des r\u00e9sistances<\/a>, pour les tableaux des codes et multiplicateurs EIA-96, ainsi que pour la remarque indiquant que les marquages ne sont pas enti\u00e8rement standardis\u00e9s. Consult\u00e9 le 21\/10\/2026.<\/li>\n\n\n\n<li>SparkFun, <a href=\"https:\/\/learn.sparkfun.com\/tutorials\/resistors\/decoding-resistor-markings\">D\u00e9codage des marquages des r\u00e9sistances<\/a>, pour les lettres multiplicatrices EIA-96 et les exemples de marquage E24. Consult\u00e9 le 21\/10\/2026.<\/li>\n\n\n\n<li>Yageo, <a href=\"https:\/\/www.yageo.com\/en\/Product\/Resistors\/Chip-Resistors\/Thick-Film-Resistors\/General-Purpose\/RC-Series\">RC series general-purpose thick film chip resistors<\/a>, pour la puissance et la tension de fonctionnement maximale selon la taille du bo\u00eetier utilis\u00e9es dans le tableau des bo\u00eetiers, notamment la limite de 200 V \u00e0 partir du 1206. Consult\u00e9 le 21\/10\/2026.<\/li>\n\n\n\n<li>Vishay, <a href=\"https:\/\/www.vishay.com\/doc?28372\"><em>Valeurs des s\u00e9ries normalis\u00e9es par d\u00e9cade pour les r\u00e9sistances et les condensateurs, de E3 \u00e0 E192 selon la norme IEC 60063<\/em>, document 28372<\/a>, pour la s\u00e9quence des mantisses E96 et la correspondance entre les s\u00e9ries E et les tol\u00e9rances. Consult\u00e9 le 21\/10\/2026.<\/li>\n\n\n\n<li>Abacus Select, <a href=\"https:\/\/www.abacuselect.com\/resources\/resistor-types-specs-complete-buyers-guide\/\">Types et sp\u00e9cifications des r\u00e9sistances<\/a>, pour les plages de tol\u00e9rance et de TCR des films \u00e9pais et minces. Consult\u00e9 le 21\/10\/2026.<\/li>\n\n\n\n<li>JLCPCB, <a href=\"https:\/\/jlcpcb.com\/hk\/blog\/thin-film-vs-thick-film-resistors\">Thin Film vs Thick Film Resistors<\/a>, pour la diff\u00e9rence de construction entre les proc\u00e9d\u00e9s \u00e0 film \u00e9pais et \u00e0 film mince. Consult\u00e9 le 21\/10\/2026.<\/li>\n\n\n\n<li>JK RG, <a href=\"https:\/\/jkrglo.com\/smd-resistor-package-sizes\/\">SMD Resistor Package Sizes<\/a>, pour les exigences de pr\u00e9cision de placement des composants 0201 et 01005. Consult\u00e9 le 21\/10\/2026.<\/li>\n\n\n\n<li>AIVON, <a href=\"https:\/\/www.aivon.com\/video\/pcb-basics\/pcb-tombstoning-causes-and-prevention-in-smt-assembly\">PCB Tombstoning: Causes and Prevention<\/a>, pour le m\u00e9canisme de l\u2019effet tombstone et ses causes li\u00e9es \u00e0 la conception du circuit. Consult\u00e9 le 21\/10\/2026.<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"<p>An SMD resistor is a fixed-value resistor in a leadless rectangular package that solders to pads on the surface of a printed circuit board rather than passing through holes. It is typically the most numerous component on a board, and the one most often specified from habit rather than from the datasheet. Most guides to [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":24071,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_titles_title":"SMD Resistor Guide: Codes, Sizes, Footprints and Limits","_seopress_titles_desc":"How to read any SMD resistor code, size the land pattern, and derate a chip resistor's power rating correctly for the temperature it will actually run at.","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_seopress_news_disabled":"","_seopress_video_disabled":"","_seopress_video":[],"_seopress_pro_schemas_manual":[],"_seopress_pro_rich_snippets_disable_all":"","_seopress_pro_rich_snippets_disable":[],"_seopress_pro_schemas":[],"footnotes":""},"categories":[14,2],"tags":[],"class_list":["post-24068","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-electronic-circuit","category-pcb-design"],"acf":[],"meta_box":[],"_links":{"self":[{"href":"https:\/\/lead-pcb.com\/fr\/wp-json\/wp\/v2\/posts\/24068","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lead-pcb.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lead-pcb.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lead-pcb.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lead-pcb.com\/fr\/wp-json\/wp\/v2\/comments?post=24068"}],"version-history":[{"count":0,"href":"https:\/\/lead-pcb.com\/fr\/wp-json\/wp\/v2\/posts\/24068\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lead-pcb.com\/fr\/wp-json\/wp\/v2\/media\/24071"}],"wp:attachment":[{"href":"https:\/\/lead-pcb.com\/fr\/wp-json\/wp\/v2\/media?parent=24068"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lead-pcb.com\/fr\/wp-json\/wp\/v2\/categories?post=24068"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lead-pcb.com\/fr\/wp-json\/wp\/v2\/tags?post=24068"}],"curies":[{"name":"Je suis d\u00e9sol\u00e9, je n'ai pas encore appris \u00e0 traduire ce contenu.","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}