Reverse Protection Diodes

From OpenCircuits
Revision as of 06:52, 27 September 2007 by (talk)
Jump to navigation Jump to search

index Negre xxx Video risse di femmine dragon ball hard lea de mae Servizio azienda Www porno gratis it Cazzi lunghi gratis canciones de ov7 buy dildo Yuoporn com Bocca sborrata Sex uniform horoscopos de kala suonerie sonyericsson Dragonballx it Animal fuck Gay hard ragazzo empoli Foto acconciature maschili Massaggiatrici Concorso a premi Vecchie e troie profumo alessandro acqua umts tim sony 32 crt 32 i m still in love with you mp3 Natalie bush nuda davide e golia Nokia 5200 prog scarica www futura servise it volvo a metano Female squirt Fakes italiane Foto rubate mutandine rimel www dapaura com volvere racconti con negri nirvana colonna sonora arredamenti maggi Hotel club onda Tatto maori portefranche a rovato logitech s 510 Virgilioeros Free mature video notizie rai centrino ddr2 Nudismo formentera elicottero elettrico modelli aerei ed Filmati pompini gratis concessionario mini cooper Video bocchino Donna porno Animal free sex Valtour Video alessio cantante napoletano url Disegni da colorare witch traduzione testo phantom p Promodit Donne ciccioni video de fiera inquieta Clip porno santuario s rosalia montepellegrino casalinghe in chatt Porno bondage whirlpool 356 Fighe tedesche video Piede melissa satta chi vuol essere milionario dvd domini net bjork vespertine live at royal opera house cartina germania est makin out epson c9100 sitemap risma Monologhi film Silvie lubamba nuda Porno dragonball Girls culotte con te partir occhi di santa lucia stampante samsung laser clp510 Video donne che si masturbano Hentai sakura Animali porno Tatuaggi farfalle acer videoproiettori dlp Www persomil difesa it la vedetta lombarda laura freddi Download software busta paga Giochi sexy gratis mercedes ml 500 Fotoracconti incesti map map palazzo bricherasio and mostra Pesci pericolosi mar rosso Scopata da cavallo site Video fighe vergini Disegni di tattoo Testi nino fiorello normative mpi gioco computer scaricare gratis Bundas e bucetas Free anime sexy games Scopate con cani hace tanto tiempo assegni famigliari inps Nude beach teen Alcolismo it home Orari trenitalia giuni russo mare a60 186 toshiba Personil difesa it Alice voip site Diciottenni sexy Mogli lesbiche lavatrice whirlpool 1000 giri cinema on line pronosticare Masturbazione video uscita hdmi Racconti eccitanti index Moto honda cross usata map Pompini clip amplad 2 sole di mezzanotte www carabinieri slide along time remix Esibizioniste voyeur tarassaco real joy asus a7n8xdeluxe page Fumetti erotici gratis cantante croata video page jaune Togae quoque fortitudo calendari attrici famose dello spettacolo testo sick and tired Mature big Tesi titoli foto porno estrada crossing jordan ticket restaurant dragstar yamaha Purea fava scarola pecorino url tirrenica Oroscopo cinese cane Dragonball sex link tv dvd combo Dog cum shot Naruto fumetti xxx Fica sborata quattro stracci inabili incentivi gatto nero gatto bianco midi film Donne in calore aeg lavatrice Suore che scopano page Frasi di auguri primo compleanno Myscenecom withney Gladiatore tatuaggio Misha barton nuda istituto marco polo fotochatter Santino saronno fiat panda km 0 multijet Tv streaming adult aline barros windows professional dice lui lei Casalinghe-pornoit Dsquared shoes daniela turchetti auto laguna fiat stilo jtd gt jeans dolce gabbana uomo abbigliamento site Belle donne che scopano hamlet pen drive 4 gb homepage mortal kombat distruzione totale {| align=right |- | TPS Voltage Regulator |} Description:
These large current, high voltage diodes can be used for a multitude of purposes. Really, we just use them for reverse polarization protection.

Most systems that we play with are DC based - whatever board requires 'X' voltage (3.3V for example). The board expects the DC voltage in a certain way. VCC in one spot, ground in another. If you reverse this (attaching VCC where GND should be, etc) BAD things happen. If you're lucky, there will be a massive short somewhere and nothing major will smoke. If you're unlucky, the board will go up in smoke and some things might explode. In practice, most things heat up (no smoke or explosion), but are instantly killed. So now you've got a board that doesn't work but it can be very hard (nye, nearly impossible) to tell what is damaged and what can be fixed.

Obviously there must be a way to prevent this from happening. Enter diodes...

These pieces of silicon allow current to flow in one direction only. Quite simply, VCC is allow through but GND is not. Why don't we put a diode on every VCC? Well a diode can cause a 0.7V drop (that's what they teach you in silly eng school at least) on the power line. So if you are dealing with a really low-power system, 0.7V drop can be too much.

There are other ways to protect against reverse polarization like polarized connectors and certain voltage regulators have protection built in. But it you're designing something for mass-market where you don't know who will be connecting what, a reverse protection diode is cheap and easily designed into a board.


Here you can see the diode D3 in place.

These type diodes can also be used, four at a time, in an bridge rectifier configuration. I don't have a good image (now you do), but an bridge rectifier takes an AC signal and rectifies it to a DC signal (neat trick actually). An bridge rectifier circuit will also work with a DC supply.

Diodes come in all shapes and sizes. For this posting, we only care about cheap, bulky, large current diodes. These diodes can handle 1-2A each and are cheap. For some our mass designs, we prefer the surface mount diodes (MBRA140). The MBRA140 comes in an SMA package (hopelessly confused with the SMA antenna connector - who came up with this?!). Many other diodes come in axial packages perfect for bread boarding. They all work the same - there is an anode and a cathode. I was always told to remember the anode was the arrow and current flows in the direction of the arrow. Cool huh?

We like the MBRA140 cause it's cheap and can handle up to 1A. One amp is overkill for most applications, but that's why it's good, it'll work with most applications. If you need something less burly, Digikey/Mouser has more than plenty. Be sure to get a diode that is current rated for the max current draw of your system. If the diode is too small, it'll heat up and eventually burn out.

MBRA140 Datasheet

SFE Footprint Library

FP Name: SMA-Diode

Manufacturer Info:
International Rectifier # : MBRA140TR

Supplier Info:
Digikey part # : MBRA140CT-ND
Single Piece Price : $0.45

Related Items: