Litlhaloso tsa Resistor: Tataiso e Felletseng ea Tekheniki bakeng sa Moralo oa PCB

1. Hobaneng ha Litlhaloso tsa Resistor li le Bohlokoa ho PCB Design

Li-resistor li bonahala li le bonolo ka mokhoa o thetsang, leha ho le joalo boitšoaro ba tsona ba motlakase bo fetela hole ka nģ'ane ho boleng ba khanyetso bo tloaelehileng. Litlhaloso tse felletseng tsa resistor li kenyelletsa maemo a mamello, litekanyetso tsa matla, sebopeho sa thepa, le li-coefficients tsa mocheso tse khethollang botsitso ba potoloho tlas'a maemo a sebele a lefats'e. Ho hloleha ha boenjiniere ha ho atise ho bakoa ke boleng bo fosahetseng ba khanyetso—ho e-na le hoo, 90% ea mathata a amanang le resistor a bakoa ke kutloisiso e sa lekaneng ea liparamente tsena tsa bohlokoa.

Litlhaloso tsa Resistor li oela ka mekhahlelo e mene ea mantlha: litšobotsi tsa motlakase li hlalosa matla a motlakase le likarabo tsa hona joale, litekanyetso tsa mocheso li laola ho qhalana ha mocheso, thepa ea thepa e khethollang ho nepahala le botsitso, 'me metrics ea ts'episo e bolela esale pele ts'ebetso ea nako e telele. Tataiso ena e fa baqapi ba PCB moralo o hlophisitsoeng oa khetho ea likarolo.

2. Litlhaloso tsa Resistor ea Motlakase

2.1 Maemo a Nominal Resistance le E-Series Standards

Litekanyetso tse tloaelehileng tsa ho hanyetsa li latela tsamaiso ea E-Series, moo E6, E12, E24, E48, le E96 letoto le hlalosang li-increments tse ntseng li tsoela pele. Letoto ka leng le lumellana le mamello e itseng: E6 e fana ka ± 20% ka litekanyetso tse tšeletseng ka lilemo tse leshome, ha E96 e fana ka ± 1% ka litekanyetso tse mashome a robong a metso e tšeletseng. Likhoutu tse holimo li sebelisa linomoro tse tharo kapa tse 'ne moo "103" e bonts'ang 10kΩ le "4702" e emela 47kΩ. Lisebelisoa tse nepahetseng tse hlokang karohano ea motlakase hantle li hloka letoto la E96 ho fokotsa liphoso tse ntseng li eketseha.

2.2 Resistance Mamello

Ho mamella ho hanyetsa ho hlalosa ho kheloha ho lumelletsoeng ho tsoa ho boleng bo tloaelehileng, bo hlalositsoeng e le mefuta ea liperesente tse kang ±1% kapa ±0.1%. Marangrang a karohano ea motlakase, mamello ea motho ka mong e kopana ka bongata—sehahi sa 10kΩ/10kΩ se nang le lihahi tsa ±1% se hlahisa liphoso tse ka bang teng tsa tlhahiso ea ±2%. Li-circuits tsa analog tse nepahetseng, marang-rang a litšupiso tsa ADC, le li-amplifier tsa lisebelisoa li hloka litlhaloso tsa mamello ea ±0.1% ho boloka botšepehi ba lets'oao.

Mekhahlelo ea mantlha ea mamello ho latela theknoloji:

• Li-resistors tsa lifilimi tse teteaneng - ± 1% ho ± 5% litlhaloso tse tloaelehileng
• Thin-filimi resistors - ± 0.1% ho ± 0.5% ho nepahala ho ka finyelloang
• Metal foil resistors - ± 0.01% bakeng sa lisebelisoa tsa lisebelisoa

2.3 Temperature Coefficient of Resistance (TCR)

Coefficient ea mocheso oa khanyetso , e lekanngoang ka likarolo ka milione ka degree Celsius (ppm/°C), e lekanya ho kheloha ha khanyetso ho pholletsa le liphetoho tsa mocheso. Resistor e nang le 100 ppm/°C TCR e fetola 0.01% ka degree Celsius, e leng se etsang hore ho be le phoso ea 1% ka nako ea 100°C. Lipotoloho tsa tekanyo e nepahetseng haholo le li-voltage tse tsitsitseng tsa litšupiso li hloka likarolo tse tlase tsa TCR ho thibela ho kheloha ha tekanyo ho bakoang ke mocheso.

Khetho ea thepa e etsa qeto ea ts'ebetso ea TCR: li-resistant-filimi tse teteaneng li bonts'a 100-200 ppm/°C, filimi ea tšepe e fihlella 25-50 ppm/°C, le mefuta e fapaneng ea foil ea tšepe e fihla ka tlase ho 5 ppm/°C.

2.4 Voltage Coefficient

Voltage coefficient e hlalosa liphetoho tsa ho hanyetsa tlas'a khatello ea motlakase e sebelisoang, e fetoha ea bohlokoa lits'ebetsong tse phahameng tsa motlakase ka holimo ho 100V. Li-resistors tsa lifilimi tse teteaneng li bonts'a matla a matla a motlakase ho feta mefuta e meng ea lifilimi tse tšesaane ka lebaka la litsela tsa tsona tsa granular conductive. Li-high-voltage divider network li tlameha ho ikarabella bakeng sa liphetoho tse itšetlehileng ka motlakase tse kopantsoeng le mamello le liphello tsa mocheso.

2.5 Matla a phahameng a ho sebetsa

Matla a phahameng a ho sebetsa a theha moeli o kaholimo oa ts'ebetso e bolokehileng ea resistor, e lekantsoeng ke boholo ba sephutheloana, matla a dielectric a thepa le boleng ba ho hanyetsa. Mefuta e tloaelehileng ea SMD e tsamaisana le litekanyetso tsa motlakase: liphutheloana tsa 0402 hangata li sebetsana le 50V, 0603 e tšehetsa 75V, ha 0805 le 1206 li amohela 150V le 200V ka ho latellana. Li-circuits tse feto-fetohang tse phahameng li hloka ho fokotseha ha motlakase ho thibela ho senyeha ha dielectric.

3. Litlhaloso tsa Matla le Thermal Resistor

3.1 Tekanyetso ea Matla

Tekanyo ea matla e hlalosa bokhoni ba ho qhala bo tsoelang pele, bo baloang ka P = I²R = likamano tsa V²/R. Sebopeho sa thepa se susumetsa haholo ts'ebetso ea matla—li-resistor tsa filimi e teteaneng li fana ka conductivity e tlase ea mocheso ho feta mekhoa e meng ea filimi ea tšepe. Bokhoni bo tloaelehileng ba matla a SMD bo fapana ho latela sephutheloana:

• Paka ea 0402 - 0.063W (1/16W) matla a lekantsoeng
• Paka ea 0603 - 0.1W (1/10W) matla a lekantsoeng
• Paka ea 0805 - 0.125W (1/8W) matla a lekantsoeng
• Paka ea 1206 - 0.25W (1/4W) matla a lekantsoeng

3.2 Derating Curves

Ho fokotseha ha li-curves ho laela ho fokotsa matla ho mocheso o phahameng oa tikoloho ho thibela ho baleha ha mocheso. Bongata ba lihanyetsi tsa SMD li qala ho theoha ho 70 ° C, ho fokotsa ho qhalana ho lumelletsoeng ka mokhoa o lekanang ho ea ho zero ka mocheso o phahameng o lekantsoeng. Li-resistors tsa lifilimi tse teteaneng li bonts'a matsoapo a thellang ho feta mefuta ea lifilimi tsa tšepe ka lebaka la mefokolo ea mocheso oa substrate.

Lisebelisoa tsa likoloi le liindasteri tse sebetsang ka holimo ho 85°C tikolohong li hloka ho nyenyefatsoa ka mokhoa o hlokolosi-baqapi ba atisa ho fokotsa matla a 50% bakeng sa likarolo tse ka tšeptjoang ho lintlha tsena tse hanyetsang.

3.3 Ho hanyetsa mocheso

Ho hanyetsa mocheso ho lekanya katleho ea phetisetso ea mocheso ho tloha nthong e hanyetsang ho ea tikolohong e potolohileng, haholoholo ka PCB koporo le lipampiri tsa solder. Liphutheloana tse nyane joalo ka 0402 li bonts'a khanyetso e phahameng ea mocheso ho feta mefuta e 1206 hobane sebaka se fokotsehileng sa pad se fokotsa litsela tsa ho tsamaisa mocheso. Lisebelisoa tsa motlakase li sebelisa meaho e khethehileng e nang le mocheso o ka holimo holim'a metsi kapa lisebelisoa tsa mocheso tse ka tlaase tse fetisang mocheso ka har'a lifofane tsa koporo tse ka hare.

3.4 Litekanyetso tsa Pulse le Surge

Litlhaloso tsa litekanyetso tsa pulse li hlalosa mamello ea nako e khuts'oane ea ho jara ho feta tekanyo e tsoelang pele ea matla. Li-resistors tsa filimi e teteaneng li sebetsana le li-pulse tse khutšoane hampe ha li bapisoa le meaho ea wirewound e mamellang matla a nakoana a matla. Liketsahalo tsa morao-rao nakong ea ho qala phepelo ea motlakase hangata li senya lihanyetsi tse tlase tsa SMD taolong ea enjene le lipotolohong tsa ho tjhaja betri.

4. Litlhaloso tsa Mohanyetsi tse thehiloeng ho lintho tse bonahalang

4.1 Thick Film Resistors

Li-resistors tsa lifilimi tse teteaneng li laola lisebelisoa tsa elektroniki tsa bareki ka litšenyehelo tse tlase tsa tlhahiso le ts'ebetso e lekaneng bakeng sa lits'ebetso tse sa hlokeng letho. Likarolo tsena li bonts'a li-coefficients tsa mocheso oa 100-200 ppm/°C, mekato e phahameng ea lerata, le mamello e fokolang ea pulse ka lebaka la kaho ea tsona ea ruthenium oxide peste. Hangata baqapi ba potoloho ba sebelisa hampe lihanyetsi tsa lifilimi tse teteaneng litseleng tse nepahetseng tsa mats'oao a analoge moo litlhaloso tsa bona tsa mohanyetsi li nyenyefatsang ho nepahala ha sistimi.

4.2 Thin Film Resistors

Theknoloji ea filimi e tšesaane e kenya likarolo tsa alloy ea tšepe ka lits'ebetso tsa vacuum, ho fihlela litlhaloso tse phahameng ha li bapisoa le mefuta e meng ea lifilimi tse teteaneng. Lihanyetsi tsena li fana ka li-coefficients tsa mocheso oa 25-50 ppm / ° C, lerata le fokotsehileng la Johnson, le litekanyetso tse matla tsa ho mamella ho theosa ho ± 0.1%. Li-circuits tsa maqhubu a phahameng le marang-rang a nepahetseng a ADC a rua molemo ka botsitso ba filimi e tšesaane.

4.3 Filimi ea Metal le Metal Foil

Bahanyetsi ba lifilimi tsa tšepe ba fana ka litlhaloso tsa boemo ba laboratori tse nang le li-coefficients tsa mocheso tse fihlang ± 25 ppm/°C le botsitso bo ikhethang ba nako e telele. Mehaho ea tšepe ea tšepe e fihlela ±0.2 ppm/°C ts'ebetso bakeng sa lisebelisoa tsa boemo ba lisebelisoa tse hlokang ho nepahala ho fetisisa. Marang-rang a lemohang hona joale, litšupiso tse nepahetseng tsa motlakase, le litekanyetso tsa calibration li sebelisa lintlha tsena tsa premium resistor moo ho nepahala ha tekanyo ho lokafatsang litšenyehelo tse holimo.

4.4 Wirewound Resistors

Lisebelisoa tsa Wirewound li sebetsana le maemo a phahameng a matla le maqhubu a phallang ka nichrome kapa leqeba le tšoanang la terata ea alloy holim'a li-cores tsa ceramic. Likarolo tsena li ipabola phepelong ea matla, lilaoli tsa makoloi, le lits'ebetso tsa taolo ea betri tse hlokang mamello e matla ea pulse. Lisebelisoa tsa maqhubu a phahameng li tlameha ho qoba mefuta ea li-wirewound hobane inductance ea bona ea tlhaho e baka liphapang tsa impedance le oscillation e ka bang teng.

5. Litlhaloso tsa Tšepahala le Mechanical Resistor

5.1 Boholo ba Sephutheloana

Litekanyo tsa sephutheloana sa 'mele li ama ka kotloloho ho felloa ke matla, taolo ea mocheso, ho sebetsana le motlakase le ho tiea ha mochini. Litlhaloso tse tloaelehileng tsa metric li latela bolelele × bophara ba sebopeho ka limilimithara: 0402 litekanyo 1.0×0.5mm, 0603 spans 1.6×0.8mm, 0805 e atolosa 2.0×1.25mm, ha 1206 e fihla ho 3.2×1.6mm. Liphutheloana tse kholo li fana ka ho hasana ha mocheso o phahameng, ho eketsa matla a ho khomarela pad, le ho ntlafatsa ho arohana ha motlakase pakeng tsa li-terminals.

5.2 Botsitso ba Nako e Telele

Botsitso ba nako e telele bo hlalosa liphetoho tsa boleng ba khanyetso ka nako e telele ea ts'ebetso tlas'a khatello ea tikoloho. Lihanyetsi tsa lifilimi tse teteaneng hangata li hoholeha ka 1-2% ho feta lihora tse 1000 maemong a lekantsoeng, ha mefuta e fapaneng ea lifilimi tse tšesaane e boloka botsitso ba ± 0.1%, 'me mefuta ea foil ea tšepe e fihlela ± 0.005% ho nepahala. Mongobo o phahameng, ho palama libaesekele, le ts'ebetso e tsitsitseng ea motlakase o phahameng li potlakisa lits'ebetso tsa botsofali ho latela litlhaloso tsa resistor.

5.3 Boemo ba Mocheso o Tsamaisang

Litlhaloso tse tloaelehileng tsa mohanyetsi li koahela -55°C ho ea ho +125°C libaka tse tikolohong bakeng sa lits'ebetso tsa khoebo, ha thuto ea likoloi ea AEC-Q200 e hloka -40°C ho isa +155°C netefatso ea ts'ebetso. Lithempereichara tse feteletseng ka nako e le 'ngoe li ama ho hoholeha ha TCR, li-curve tse fokotsang matla, le maemo a lerata a tlhaho ka mekhoa e kopaneng.

5.4 Ts'ebetso ea Lerata

Lerata la Resistor le bonahala e le lerata le chesang la Johnson-Nyquist le lerata le feteletseng le tsoang ho li-discontinuities. Mehaho ea lifilimi tse teteaneng e hlahisa mekato e phahameng ea lerata e nyenyefatsang botšepehi ba matšoao a boemo bo tlase ho li-circuits tsa amplifier tse sebetsang le lipheletsong tse ka pele tsa ADC. Meralo e nepahetseng ea ho hanyetsa e fokotsa lerata le feteletseng ka ho fana ka filimi e tšoanang e le ea bohlokoa bakeng sa litsamaiso tsa tekanyo e phahameng ea qeto.

6. Ho Khetha Litlhaloso tsa Resistor bakeng sa Likopo tsa PCB

6.1 Lipotoloho tsa Dijithale

Disekete tsa logic tsa dijithale di mamella di-resistor tse tloaelehileng tsa filimi e teteaneng tse nang le mamello ya ±1% le di-coefficient tsa mocheso wa 100 ppm/°C bakeng sa mesebetsi ya ho hula, ho hula le ho emisa. Ho qhala ha motlakase ho ntse ho le honyenyane—diphutheloana tsa 0402 kapa 0603 di lekane bakeng sa ho lokisa matshwao a tlwaelehileng ha ho ntse ho bolokwa bokgoni ba ditjeo.

6.2 Lipotoloho tsa Analog tse nepahetseng

Ts'ebetso ea matšoao a analog , litšupiso tsa motlakase o nepahetseng, le tlhoko ea lintlha tse phahameng tsa ho fumana data tse nang le qeto e phahameng tse hanyetsanang le filimi e tšesaane tse nang le mamello ea ±0.1% le li-coefficients tsa mocheso tse ka tlase ho 50 ppm/°C. Mabota a lerata le tlase le botsitso bo botle ba nako e telele li lokafatsa boleng ba litšenyehelo moo botšepehi ba lets'oao bo khethollang ts'ebetso ea sistimi ka kotloloho.

6.3 Likopo tse Matla a Phahameng

Disekete tsa taolo ya enjene , othomathike ya diindasteri, le conditioning ya motlakase di hloka di-resistors tsa terata kapa tsa filimi ya tshepe ka hara dipakete tse kgolo tse lekantsweng bakeng sa ho qhalana ha matla a phahameng ka ho tswelang pele. Ditlhaloso tsena tsa resistor di beha pele mamello ya pulse le taolo ya mocheso—dipakete tse 1206 kapa tse kgolo tse kentsweng hodima metsi di fana ka tsamaiso e hlokahalang ya matla ka mathoko a lekaneng a ho qhalana.

6.4 Litsamaiso tse Phahameng ka ho Fetisisa

Dipotoloho tsa motlakase o phahameng tse fetang 100V tse hlokang di-resistor tse nang le ditekanyetso tse loketseng tsa motlakase, dibaka tse lekaneng tsa ho kgurumetsa, le dintlha tse bolokang kgatello. Baqapi ba tlameha ho totobatsa diphutheloana tse kgolo tse kang 1206 kapa 2010 ho fihlella sebaka se hlokahalang sa dielectric ha ba ntse ba ikarabella bakeng sa ditlamorao tsa motlakase.

6.5 Maikutlo a Hona Joale

Lisebelisoa tsa morao-rao li hloka litekanyetso tse phahameng tsa ho hanyetsa tse nang le mamello e thata-tšepe ea tšepe kapa lisebelisoa tse 'nè tsa ho kopanya Kelvin li felisa liphoso tsa ho hanyetsa lead. Litlhaloso tsena tse khethehileng tsa ho hanyetsa li fana ka boleng ba sub-1mΩ ka mamello ea ± 0.1% le li-coefficients tse fokolang tsa mocheso tse hlokahalang bakeng sa ho lekola matla ka nepo.

7. Qetello: Ho utloisisa Litlhaloso tsa Resistor

Likarolo tse tharo tsa ts'ebetso ea bohlokoa tsa mamello, coefficient ea mocheso, le lintlha tsa matla li etsa qeto ea hore na bahanyetsi ba boloka boitšoaro bo itseng bophelo bohle ba sehlahisoa. Baqapi ba hlahlobang feela khanyetso ea lebitso le boholo ba sephutheloana ba tla kopana le liphoso tsa tšimo ho tsoa khatellong ea mocheso, ho hoholeha kapa ho putlama ha motlakase. Litlamorao tse kopaneng tsa li-parameter tse fapaneng li theha boits'oaro ba boemo ba sistimi bo fapaneng haholo le mefuta e bonolo ea theory.

Khetho ea lintho tse bonahalang e sitisa ts'ebetso e ka fihlellehang: lihanyetsi tsa lifilimi tse teteaneng ha li khone ho ts'oana le ho nepahala ha filimi ho sa tsotelehe boholo ba sephutheloana, ha meaho ea wirewound e hlahisa inductance ea parasitic e sa lokelang lits'ebetso tse phahameng haholo.

Tlhaloso e atlehileng ea resistor e hloka ho bapisa litšobotsi tsa likarolo le maemo a 'nete a khatello ea potoloho ho kenyeletsoa le maemo a mocheso a tikoloho, li-voltage transients, le litlhoko tsa botsitso ba nako e telele. Ho Highleap Electronics, sehlopha sa rona sa boenjiniere se fana ka moralo oa litlhahlobo tsa tlhahiso ho ntlafatsa likhetho tsa likarolo bakeng sa ts'epo.