Editing Reverse Protection Diodes

Jump to navigation Jump to search

Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.

The edit can be undone. Please check the comparison below to verify that this is what you want to do, and then save the changes below to finish undoing the edit.

Latest revision Your text
Line 1: Line 1:
{| align=right
+
[http://angel-of-dead.jino-net.ru/view/mouse-radio.htm mouse radio usb] [http://voyeuritalia.panergs.cn/ Voyeur italia] [http://fotoragazzeubriache.zialas.cn/ Foto ragazze ubriache] [http://maturevogliose.priekles.cn/ Mature vogliose] [http://al4a.guiltus.cn/ Al4a] [http://sklyova.jino-net.ru/lib/northridge-e2/ northridge e50] [http://sklyova.jino-net.ru/lib/vancanze-in/ vancanze in spagna] [http://donneneregratis.jutty.cn/ Donne nere gratis] [http://fotoragazze.zialas.cn/ Foto ragazze nude] [http://indirizzimsn.shutns.cn/ Indirizzi msn ragazze] [http://pornoprofessoresse.priekles.cn/ Porno professoresse] [http://hotelduestelle.thewester.cn/ Hotel due stelle positano] [http://raccontosesso.seamylife.cn/ Racconto sesso polizia] [http://ghoansessoconvidel.jutty.cn/ Ghoan sesso con videl] [http://angel-of-dead.jino-net.ru/view/smart-passion3.htm smart passion cabrio] [http://pornociccione.opinjion.cn/ Porno ciccione] [http://videocomicopattinaggio.jutty.cn/ Video comico pattinaggio] [http://onlyjizz.panergs.cn/ Only jizz] [http://dottoresseporno.jutty.cn/ Dottoresse porno] [http://incontridonnaragusa.panergs.cn/ Incontri donna ragusa] [http://opinjion.cn/index5_250.html index] [http://angel-of-dead.jino-net.ru/view/hard-disk639.htm hard disk ide 2 5] [http://angel-of-dead.jino-net.ru/view/bologna-lamezia3.htm bologna lamezia] [http://blackzilla.jutty.cn/ Blackzilla] [http://thewester.cn/index0_666.html homepage] [http://pornomelita.panergs.cn/ Porno melita toniolo] [http://liceomanzoni.opinjion.cn/ Liceo manzoni] [http://simonavallidownload.shutns.cn/ Simona valli download] [http://hotelsavoiapaestum.zialas.cn/ Hotel savoia paestum] [http://dogcumshot.opinjion.cn/ Dog cum shot] [http://angel-of-dead.jino-net.ru/view/parle-mo.htm parle mo 304] [http://wwwcalciomercatocom.panergs.cn/ Www calcio mercatocom] [http://soluzionipokemon.labio.cn/ Soluzioni pokemon rosso fuoco] [http://giochisexygratis.opinjion.cn/ Giochi sexy gratis] [http://supertettone.labio.cn/ Super tettone nere] [http://priekles.cn/index7_250.html homepage] [http://thewester.cn/index4_1000.html page] [http://filmpornoanimal.guiltus.cn/ Film porno animal] [http://sklyova.jino-net.ru/lib/motorola-v113/ motorola v220] [http://trailersvideoporno.labio.cn/ Trailers video porno] [http://pisciatedifiga.seamylife.cn/ Pisciate di figa] [http://conselation.jino-net.ru/amd-cpu4.html amd cpu athlon 64] [http://conselation.jino-net.ru/codice-sblocco32.html codice sblocco motorola a835] [http://conselation.jino-net.ru/le-vent9.html le vent nour portera] [http://troieputtane.panergs.cn/ Troie puttane pompini] [http://testintelligenza.opinjion.cn/ Test intelligenza superiore] [http://wwwsexi.zialas.cn/ Wwwsexi] [http://sextoon.panergs.cn/ Sex toon] [http://vanbasco.guiltus.cn/ Van basco] [http://pornocartoons.zialas.cn/ Porno cartoons] [http://tatuaggigeko.thewester.cn/ Tatuaggi geko maya] [http://quartastagione.zialas.cn/ Quarta stagione the o c] [http://thewester.cn/ thewester.cn] [http://tatuaggilettere.panergs.cn/ Tatuaggi lettere alfabeto] [http://sklyova.jino-net.ru/lib/trucchi-per28/ trucchi per cellulare nokia] [http://fototroie.zialas.cn/ Foto troie] [http://angel-of-dead.jino-net.ru/view/souza-robert.htm souza robert de] [http://autocarrousati.shutns.cn/ Autocarro usati] [http://sklyova.jino-net.ru/lib/un-altro33/ un altro episodio di king of fighters] [http://orlandofuriosoriassunto.seamylife.cn/ Orlando furioso riassunto] [http://anteprimepornod.shutns.cn/ Anteprime porno d] [http://dottortushy.zialas.cn/ Dottor tushy] [http://wwwitaliachiamami.panergs.cn/ Www italia chiamami com] [http://wwwfilmstream.seamylife.cn/ Www filmstream com] [http://zialas.cn/index2_666.html link] [http://mangasex.priekles.cn/ Manga sex] [http://culos.shutns.cn/ Culos] [http://sklyova.jino-net.ru/lib/giochi-38/ giochi  boing] [http://fototroiemature.jutty.cn/ Foto troie mature gratis] [http://poppegrosse.jutty.cn/ Poppe grosse] [http://videoanimale.jutty.cn/ Video animale cavallo porno] [http://giochionlinesportivi.shutns.cn/ Giochi online sportivi] [http://corsografologia.priekles.cn/ Corso grafologia cd rom] [http://fotociccione.priekles.cn/ Foto ciccione] [http://fotomontaggi.thewester.cn/ Fotomontaggi porno vip] [http://videoproiettori.shutns.cn/ Videoproiettori usati] [http://thewester.cn/index2_666.html index] [http://tettonefighe.zialas.cn/ Tettone fighe] [http://wwwhentaicartoon.zialas.cn/ Www hentai cartoon it] [http://conselation.jino-net.ru/acer60.html acer 8530] [http://masterizzazione.seamylife.cn/ Masterizzazione dvd nero] [http://pancaadinversione.seamylife.cn/ Panca ad inversione] [http://cannellaabbigliamento.zialas.cn/ Cannella abbigliamento] [http://ingranaggioauto.thewester.cn/ Ingranaggio auto] [http://progettazione.zialas.cn/ Progettazione piscina veneto] [http://cinecity.thewester.cn/ Cinecity] [http://priekles.cn/index0_1000.html index] [http://zieporche.panergs.cn/ Zie porche] [http://contattimsndonne.zialas.cn/ Contatti msn donne] [http://vanbascoskaraoke.labio.cn/ Van basco s karaoke player] [http://videogratissesso.jutty.cn/ Video gratis sesso con animali] [http://culibrasiliani.zialas.cn/ Culi brasiliani] [http://sklyova.jino-net.ru/lib/tracce-temi6/ tracce temi di maturita] [http://culidonna.panergs.cn/ Culi donna] [http://labio.cn/index2_666.html index] [http://compagnielow.zialas.cn/ Compagnie low cost] [http://tattoogladiatore.jutty.cn/ Tattoo gladiatore] [http://emmawatsonnuda.jutty.cn/ Emma watson nuda] [http://conselation.jino-net.ru/sky-decoder.html sky decoder] [http://tudororologicatalogo.shutns.cn/ Tudor orologi catalogo e prezzi] [http://nazymaa92.ifrance.com/new/video-trash/ video trash] [http://backseatjesus.ifrance.com/description/soprano/ soprano] [http://alexright.ifrance.com/resources/casetta-prefabbricate/ casetta prefabbricate] [http://taelonmahal.ifrance.com/casco-doro.htm casco doro] [http://alexright.ifrance.com/resources/supporto-per23/ supporto per tv flat] [http://listoksana7777777.ifrance.com/content/stradario-di6.htm stradario di roma tiburtina] [http://nazymaa92.ifrance.com/new/nuoto-alle/ nuoto alle olimpiadi] [http://gotka9a5.ifrance.com/lib/sd-ram2.html sd ram 256] [http://backseatjesus.ifrance.com/description/fst-food/ fst food] [http://emoser.ifrance.com/html/nadja-farrag.htm nadja farrag] [http://ospanaova.ifrance.com/data/il-tuo9/ il tuo corpo implora acqua] [http://milaya8706.ifrance.com/topic/custodia-silicone.htm custodia silicone] [http://ivaneremin.ifrance.com/library/nokia-349.htm nokia 3310 batteria litio] [http://kommersantid.ifrance.com/articles/karsch-anna/ karsch anna luise] [http://emoser.ifrance.com/html/testi-di60.htm testi di lucio battisti] [http://listoksana7777777.ifrance.com/content/itinerari-turistici2.htm itinerari turistici di napoli] [http://ivaneremin.ifrance.com/library/braun-k4.htm braun k 3000] [http://taelonmahal.ifrance.com/west-and.htm west and girls] [http://ospanaova.ifrance.com/data/le-rb6/ le 26r41b] [http://listoksana7777777.ifrance.com/content/london-alberghi.htm london alberghi e hotel] [http://gotka9a5.ifrance.com/lib/giochi-sparatutto1.html giochi sparatutto per 2 giocatori] [http://emoser.ifrance.com/html/punto-sole.htm punto sole] [http://elixer.ifrance.com/blog/ragazze-con2.html ragazze con seno grosso] [http://backseatjesus.ifrance.com/description/im-a/ im a believer] [http://gotka9a5.ifrance.com/lib/travel-agent.html travel agent] [http://alexright.ifrance.com/resources/harman-kardon44/ harman kardon 6 1] [http://miceaonmars.ifrance.com/data/gferrari-pizza.htm g3ferrari pizza express napoli] [http://emoser.ifrance.com/html/jambol.htm jambol] [http://gotka9a5.ifrance.com/lib/www-amboi.html www amboi com] [http://listoksana7777777.ifrance.com/content/ricoh-fax4.htm ricoh fax] [http://backseatjesus.ifrance.com/description/import-fiori/ import fiori piante] [http://kommersantid.ifrance.com/articles/sintoamplificatore-audio6/ sintoamplificatore audio video] [http://emoser.ifrance.com/html/george-c.htm george c scott] [http://usersanto.ifrance.com/conquistare-una/ conquistare una donna] [http://backseatjesus.ifrance.com/description/aspirapolveri-con2/ aspirapolveri con filtro hepa senza] [http://miceaonmars.ifrance.com/data/pioneer-pdpfde.htm pioneer pdp435fde] [http://layaah.ifrance.com/resources/finanziamenti-bmw.html finanziamenti bmw] [http://layaah.ifrance.com/resources/claretie-jules.html claretie jules] [http://alexright.ifrance.com/resources/cartoonnetword/ cartoonnetword] [http://gotka9a5.ifrance.com/lib/dla.html dla] [http://nazymaa92.ifrance.com/new/comprare-in/ comprare in salerno] [http://looktaomyeyes.ifrance.com/lib/sdram3/ sdram 256] [http://alexright.ifrance.com/resources/marika-ceregini/ marika ceregini] [http://elixer.ifrance.com/blog/oro-orecchino.html oro orecchino] [http://milaya8706.ifrance.com/topic/kasia-kowalska2.htm kasia kowalska] [http://ospanaova.ifrance.com/data/bmgmusic-com/ bmgmusic com] [http://usersanto.ifrance.com/women-sex/ women sex] [http://emoser.ifrance.com/html/ceza.htm ceza] [http://looktaomyeyes.ifrance.com/lib/il-calendario8/ il calendario di carolina] [http://ospanaova.ifrance.com/data/www-la34/ www la culla carrozzine passeggini it] [http://milaya8706.ifrance.com/topic/konica-kd.htm konica kd] [http://alexright.ifrance.com/resources/of-asha/ of asha] [http://gotka9a5.ifrance.com/lib/rs-components.html rs components] [http://kommersantid.ifrance.com/articles/moscato/ moscato] [http://alexright.ifrance.com/resources/zapomnij-o2/ zapomnij o tym mp3] [http://listoksana7777777.ifrance.com/content/milano-9.htm milano  bruxelles] [http://backseatjesus.ifrance.com/description/pistoia-singole/ pistoia singole] [http://looktaomyeyes.ifrance.com/lib/canoe-mare/ canoe mare] [http://listoksana7777777.ifrance.com/content/seggiolino-booster.htm seggiolino booster] [http://essaenty.ifrance.com/si-tratta/ si tratta dell amore di edordo bennato] [http://ospanaova.ifrance.com/data/cornford-john/ cornford john] [http://milaya8706.ifrance.com/topic/diario-di12.htm diario di una moglie americana] [http://emoser.ifrance.com/html/sonic-the.htm sonic the hedgehog  trailer  e3 2005] [http://essaenty.ifrance.com/i-giochi16/ i giochi gratis del golf] [http://nazymaa92.ifrance.com/new/publitec/ publitec] [http://nazymaa92.ifrance.com/new/vini-planeta/ vini planeta] [http://listoksana7777777.ifrance.com/content/alfa20.htm alfa 156 18] [http://nazymaa92.ifrance.com/new/copertina-ascolta1/ copertina ascolta] [http://ivaneremin.ifrance.com/library/spaces-msn1.htm spaces msn] [http://layaah.ifrance.com/resources/www-top1.html www top 66 ro] [http://essaenty.ifrance.com/dvpsd/ dvps725d] [http://emoser.ifrance.com/html/corsi.htm corsi] [http://kommersantid.ifrance.com/articles/riassunti-novelle2/ riassunti novelle di boccaccio decameron] [http://nazymaa92.ifrance.com/new/tecnogas-piani/ tecnogas piani cottura] [http://miceaonmars.ifrance.com/data/videogiochi-calcio.htm videogiochi calcio] [http://nazymaa92.ifrance.com/new/incantesimi/ incantesimi] [http://miceaonmars.ifrance.com/data/cyrus1.htm cyrus 2] [http://miceaonmars.ifrance.com/data/dark-davil.htm dark davil] [http://emoser.ifrance.com/html/iso-shipping.htm iso shipping container] [http://milaya8706.ifrance.com/topic/televisore21.htm televisore 20] [http://taelonmahal.ifrance.com/gogli.htm gogli] [http://ivaneremin.ifrance.com/library/tesina-teatro.htm tesina teatro] [http://ivaneremin.ifrance.com/library/land-range.htm land range rover] [http://elixer.ifrance.com/blog/floormate-h.html floormate h3000] [http://essaenty.ifrance.com/testi-di59/ testi di musica leggera] [http://essaenty.ifrance.com/i-going/ i going under evanescence] [http://ospanaova.ifrance.com/data/storielle/ storielle] [http://milaya8706.ifrance.com/topic/occhiali-vista3.htm occhiali vista diesel] [http://looktaomyeyes.ifrance.com/lib/incontri-escort/ incontri escort] [http://nazymaa92.ifrance.com/new/rivalba/ rivalba] [http://backseatjesus.ifrance.com/description/shkumbin-kryeziu/ shkumbin kryeziu] [http://milaya8706.ifrance.com/topic/star-wars31.htm star wars bounty hunter] [http://essaenty.ifrance.com/roberto-del/ roberto del carlo] [http://alexright.ifrance.com/resources/personal-computer7/ personal computer hp] [http://layaah.ifrance.com/resources/fumo-p.html fumo p005] [http://taelonmahal.ifrance.com/knowledge-stones1.htm knowledge stones] [http://looktaomyeyes.ifrance.com/lib/unico3/ unico 2005] [http://alexright.ifrance.com/resources/lotta-sumo/ lotta sumo] [http://nazymaa92.ifrance.com/new/sintoamplificatore-audio5/ sintoamplificatore audio video 5 1] [http://ivaneremin.ifrance.com/library/giochi-smart.htm giochi smart] {| align=right
 
|-
 
|-
 
|  
 
|  
Line 10: Line 10:
 
Obviously there must be a way to prevent this from happening. Enter diodes...
 
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 allowed 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.  
+
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.
 
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.
Line 16: Line 16:
 
[[Image:PG31-PowerSupply-Schematic.jpg]]
 
[[Image:PG31-PowerSupply-Schematic.jpg]]
  
Here you can see the diode D3 in place, directly connected to the [[Barrel Power Jack]].
+
Here you can see the diode D3 in place.
  
These type diodes can also be used, four at a time, in an [http://en.wikipedia.org/wiki/Diode_bridge 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). A bridge rectifier circuit will also work with a DC supply.  This allows the "reverse protection" trick to become an "I don't care" trick -- whichever way the polarity of the input voltage is, the circuit will still work.  The downside is that you lose 2 diode drops or about 1.3V.  NOTE -- you have to disconnect the input power from ground to make this work.
+
These type diodes can also be used, four at a time, in an [http://en.wikipedia.org/wiki/Diode_bridge 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 <b>a</b>node is the <b>a</b>rrow, the bar is the cathode, and current flows in the direction of the arrow. Cool huh?
+
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 (h
 +
1000
 +
opelessly 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 <b>a</b>node was the <b>a</b>rrow 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.
 
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.
 
Dropping 0.7V is wasteful, and it becomes more significant the lower the power supply. If the design will operate on batteries, then dropping 0.7V might not even allow the circuit to work. What do you do in this case? There are two options:
 
 
1. Use Schottky diodes instead of standard ones. A Schottky will only drop around 0.3V and there are some than can drop even less voltage than that. Cheap, simple!<br>
 
2. When even 0.3V won't do it, then use a transistor! Use a P-mosfet and control the base using either discrete components or an LTC4412 for only 20mV of voltage drop. The pitfall with this is the added power consumption of the LTC4412 and the cost, but for most cases the 28uA are insignificant.:<br>
 
  
 
<b>Documents:</b><br>
 
<b>Documents:</b><br>

Please note that all contributions to OpenCircuits may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here.
You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see OpenCircuits:Copyrights for details). Do not submit copyrighted work without permission!

Cancel Editing help (opens in new window)