El diodo de selenio es un diodo rectificador bastante antiguo, que fue creado en 1933 para ser utilizado como rectificador, sustituyendo las antiguas válvulas rectificadoras en fuentes de alimentación de alta corriente como, por ejemplo, cargadores de batería

Durante cierto tiempo, fuentes de alimentación de muchos equipos ya usaban diodos rectificadores en lugar de las válvulas, como una solución más eficiente para obtener corriente continua.

Estos diodos estaban hechos de un material semiconductor, hoy no más usado, el selenio.

Los equivalentes modernos de estos diodos son los diodos de silicio, que además de tener mucha mayor capacidad de corriente en algunos casos, también son componentes baratos.

En la figura 1 tenemos los aspectos de estos diodos.

 

Figura 1 - Diodos de selenio
Figura 1 - Diodos de selenio

 

Estos diodos están formados por pilas de placas de aluminio o acero dotadas de una finísima capa de níquel o bismuto.

En esta capa hay un dopaje de selenio que dota la estructura de propiedades semiconductoras, funcionando como un diodo.

Cada par de placas funciona como un diodo con una tensión inversa máxima del orden de 20 V. En la figura 2 tenemos la estructura de ese diodo.

 

Figura 2 - Estructura del diodo de selenio
Figura 2 - Estructura del diodo de selenio

 

Para sustituir un diodo de este tipo por uno de silicio, se debe verificar la tensión inversa de pico y la corriente. Esta información normalmente puede obtenerse por el simple análisis del circuito en el que se encuentra.

En la figura 3 tenemos una fuente de alimentación variable de una antigua Radio Electronics, usando diodos de selenio de 65 mA.

 

Figura 3 - Fuente de alimentación de alta tensión con diodos de selenio
Figura 3 - Fuente de alimentación de alta tensión con diodos de selenio

 

Esta fuente se utilizaba en equipos valvulados y en lugar de los diodos de selenio se pueden utilizar equivalentes modernos de silicio, como los 1N4004.

 

Curiosidad - El olor del selenio

Una curiosidad es el fortísimo olor de "huevo podrido" producido por los diodos de selenio cuando se quema. En algunos casos, la gente tenía que dejar el lugar rápidamente, ya que era insoportable. Un componente no amigable para el medio ambiente.

 

 

18.924MBMemory Usage40.84msRequest Duration
Joomla! Version5.2.3
PHP Version8.3.20
Identityguest
Response200
Templatecassiopeia
Database
Server
mysql
Version
10.5.22-MariaDB
Collation
latin1_swedish_ci
Conn Collation
utf8mb4_general_ci
$_GET
[]
$_POST
[]
$_SESSION
array:1 [ "joomla" => "***redacted***" ]
$_COOKIE
[]
$_SERVER
array:49 [ "USER" => "apache" "HOME" => "/usr/share/httpd" "PATH_TRANSLATED" => "redirect:/ind...
session
array:3 [ "counter" => 1 "timer" => array:3 [ "start" => 1748995024 "last" => 1748995024...
registry
array:3 [ "data" => [] "initialized" => false "separator" => "." ]
user
array:21 [ "id" => 0 "name" => null "username" => null "email" => null "password" => "***r...
  • afterLoad (85.22KB) (229μs)
  • afterInitialise (1.14MB) (3.83ms)
  • afterRoute (179.21KB) (940μs)
  • beforeRenderComponent com_content (100.98KB) (454μs)
  • Before Access::preloadComponents (all components) (33.45KB) (221μs)
  • After Access::preloadComponents (all components) (107.06KB) (364μs)
  • Before Access::preloadPermissions (com_content) (1.57KB) (9μs)
  • After Access::preloadPermissions (com_content) (16.22MB) (19.12ms)
  • Before Access::getAssetRules (id:235 name:com_content.article.9918) (514.65KB) (636μs)
  • After Access::getAssetRules (id:235 name:com_content.article.9918) (7.38KB) (48μs)
  • afterRenderComponent com_content (375.29KB) (7.09ms)
  • afterDispatch (2.25KB) (56μs)
  • beforeRenderRawModule mod_articles_category (Banco de Circuitos) (358.53KB) (1.69ms)
  • afterRenderRawModule mod_articles_category (Banco de Circuitos) (79.43KB) (352μs)
  • beforeRenderRawModule mod_finder (Busca_inteligente) (5.9KB) (96μs)
  • afterRenderRawModule mod_finder (Busca_inteligente) (64.9KB) (1.22ms)
  • beforeRenderModule mod_articles_category (Banco de Circuitos) (9.27KB) (591μs)
  • afterRenderModule mod_articles_category (Banco de Circuitos) (5.47KB) (83μs)
  • beforeRenderModule mod_finder (Busca_inteligente) (6.64KB) (194μs)
  • afterRenderModule mod_finder (Busca_inteligente) (4.75KB) (53μs)
  • afterRender (249.75KB) (3.46ms)
  • 1 x After Access::preloadPermissions (com_content) (16.22MB) (46.81%)
    19.12ms
    1 x afterRenderComponent com_content (375.29KB) (17.35%)
    7.09ms
    1 x afterInitialise (1.14MB) (9.37%)
    3.83ms
    1 x afterRender (249.75KB) (8.48%)
    3.46ms
    1 x beforeRenderRawModule mod_articles_category (Banco de Circuitos) (358.53KB) (4.13%)
    1.69ms
    1 x afterRenderRawModule mod_finder (Busca_inteligente) (64.9KB) (2.98%)
    1.22ms
    1 x afterRoute (179.21KB) (2.3%)
    940μs
    1 x Before Access::getAssetRules (id:235 name:com_content.article.9918) (514.65KB) (1.56%)
    636μs
    1 x beforeRenderModule mod_articles_category (Banco de Circuitos) (9.27KB) (1.45%)
    591μs
    1 x beforeRenderComponent com_content (100.98KB) (1.11%)
    454μs
    1 x After Access::preloadComponents (all components) (107.06KB) (0.89%)
    364μs
    1 x afterRenderRawModule mod_articles_category (Banco de Circuitos) (79.43KB) (0.86%)
    352μs
    1 x afterLoad (85.22KB) (0.56%)
    229μs
    1 x Before Access::preloadComponents (all components) (33.45KB) (0.54%)
    221μs
    1 x beforeRenderModule mod_finder (Busca_inteligente) (6.64KB) (0.47%)
    194μs
    1 x beforeRenderRawModule mod_finder (Busca_inteligente) (5.9KB) (0.23%)
    96μs
    1 x afterRenderModule mod_articles_category (Banco de Circuitos) (5.47KB) (0.2%)
    83μs
    1 x afterDispatch (2.25KB) (0.14%)
    56μs
    1 x afterRenderModule mod_finder (Busca_inteligente) (4.75KB) (0.13%)
    53μs
    1 x After Access::getAssetRules (id:235 name:com_content.article.9918) (7.38KB) (0.12%)
    48μs
    1 x Before Access::preloadPermissions (com_content) (1.57KB) (0.02%)
    9μs
21 statements were executed, 5 of which were duplicates, 16 unique11.05ms1.55MB
  • SELECT @@SESSION.sql_mode;30μs968B/libraries/src/Session/MetadataManager.php:184Copy
  • SELECT `session_id` FROM `incbmx_session` WHERE `session_id` = :session_id LIMIT 174μs1.3KBParams/libraries/src/Session/MetadataManager.php:187Copy
  • INSERT INTO `incbmx_session` (`session_id`,`guest`,`time`,`userid`,`username`,`client_id`) VALUES (:session_id, :guest, :time, :user_id, :username, :client_id)185μs944BParams/libraries/src/Session/MetadataManager.php:260Copy
  • SELECT `id`,`rules` FROM `incbmx_viewlevels`51μs656B/libraries/src/Access/Access.php:955Copy
  • SELECT `b`.`id` FROM `incbmx_usergroups` AS `a` LEFT JOIN `incbmx_usergroups` AS `b` ON `b`.`lft` <= `a`.`lft` AND `b`.`rgt` >= `a`.`rgt` WHERE `a`.`id` = :guest66μs1.64KBParams/libraries/src/Access/Access.php:868Copy
  • SELECT `c`.`id`,`c`.`asset_id`,`c`.`access`,`c`.`alias`,`c`.`checked_out`,`c`.`checked_out_time`,`c`.`created_time`,`c`.`created_user_id`,`c`.`description`,`c`.`extension`,`c`.`hits`,`c`.`language`,`c`.`level`,`c`.`lft`,`c`.`metadata`,`c`.`metadesc`,`c`.`metakey`,`c`.`modified_time`,`c`.`note`,`c`.`params`,`c`.`parent_id`,`c`.`path`,`c`.`published`,`c`.`rgt`,`c`.`title`,`c`.`modified_user_id`,`c`.`version`, CASE WHEN CHAR_LENGTH(`c`.`alias`) != 0 THEN CONCAT_WS(':', `c`.`id`, `c`.`alias`) ELSE `c`.`id` END as `slug` FROM `incbmx_categories` AS `s` INNER JOIN `incbmx_categories` AS `c` ON (`s`.`lft` <= `c`.`lft` AND `c`.`lft` < `s`.`rgt`) OR (`c`.`lft` < `s`.`lft` AND `s`.`rgt` < `c`.`rgt`) WHERE (`c`.`extension` = :extension OR `c`.`extension` = 'system') AND `c`.`published` = 1 AND `s`.`id` = :id ORDER BY `c`.`lft`234μs20.2KBParams/libraries/src/Categories/Categories.php:375Copy
  • SELECT `id`,`name`,`rules`,`parent_id` FROM `incbmx_assets` WHERE `name` IN (:preparedArray1,:preparedArray2,:preparedArray3,:preparedArray4,:preparedArray5,:preparedArray6,:preparedArray7,:preparedArray8,:preparedArray9,:preparedArray10,:preparedArray11,:preparedArray12,:preparedArray13,:preparedArray14,:preparedArray15,:preparedArray16,:preparedArray17,:preparedArray18,:preparedArray19,:preparedArray20,:preparedArray21,:preparedArray22,:preparedArray23,:preparedArray24,:preparedArray25,:preparedArray26,:preparedArray27,:preparedArray28,:preparedArray29,:preparedArray30,:preparedArray31,:preparedArray32,:preparedArray33,:preparedArray34,:preparedArray35,:preparedArray36,:preparedArray37,:preparedArray38,:preparedArray39)214μs7.44KBParams/libraries/src/Access/Access.php:357Copy
  • SELECT `id`,`name`,`rules`,`parent_id` FROM `incbmx_assets` WHERE `name` LIKE :asset OR `name` = :extension OR `parent_id` = 07.61ms1.48MBParams/libraries/src/Access/Access.php:301Copy
  • SHOW FULL COLUMNS FROM `incbmx_content`427μs2.39KB/libraries/vendor/joomla/database/src/Mysqli/MysqliDriver.php:587Copy
  • UPDATE `incbmx_content` SET `hits` = (`hits` + 1) WHERE `id` = '9918'171μs48B/libraries/src/Table/Table.php:1348Copy
  • SELECT `a`.`id`,`a`.`asset_id`,`a`.`title`,`a`.`alias`,`a`.`introtext`,`a`.`fulltext`,`a`.`state`,`a`.`catid`,`a`.`created`,`a`.`created_by`,`a`.`created_by_alias`,`a`.`modified`,`a`.`modified_by`,`a`.`checked_out`,`a`.`checked_out_time`,`a`.`publish_up`,`a`.`publish_down`,`a`.`images`,`a`.`urls`,`a`.`attribs`,`a`.`version`,`a`.`ordering`,`a`.`metakey`,`a`.`metadesc`,`a`.`access`,`a`.`hits`,`a`.`metadata`,`a`.`featured`,`a`.`language`,`fp`.`featured_up`,`fp`.`featured_down`,`c`.`title` AS `category_title`,`c`.`alias` AS `category_alias`,`c`.`access` AS `category_access`,`c`.`language` AS `category_language`,`fp`.`ordering`,`u`.`name` AS `author`,`parent`.`title` AS `parent_title`,`parent`.`id` AS `parent_id`,`parent`.`path` AS `parent_route`,`parent`.`alias` AS `parent_alias`,`parent`.`language` AS `parent_language`,ROUND(`v`.`rating_sum` / `v`.`rating_count`, 1) AS `rating`,`v`.`rating_count` AS `rating_count` FROM `incbmx_content` AS `a` INNER JOIN `incbmx_categories` AS `c` ON `c`.`id` = `a`.`catid` LEFT JOIN `incbmx_content_frontpage` AS `fp` ON `fp`.`content_id` = `a`.`id` LEFT JOIN `incbmx_users` AS `u` ON `u`.`id` = `a`.`created_by` LEFT JOIN `incbmx_categories` AS `parent` ON `parent`.`id` = `c`.`parent_id` LEFT JOIN `incbmx_content_rating` AS `v` ON `a`.`id` = `v`.`content_id` WHERE ( (`a`.`id` = :pk AND `c`.`published` > 0) AND (`a`.`publish_up` IS NULL OR `a`.`publish_up` <= :publishUp)) AND (`a`.`publish_down` IS NULL OR `a`.`publish_down` >= :publishDown) AND `a`.`state` IN (:preparedArray1,:preparedArray2)176μs6.12KBParams/components/com_content/src/Model/ArticleModel.php:215Copy
  • SELECT `c`.`id`,`c`.`asset_id`,`c`.`access`,`c`.`alias`,`c`.`checked_out`,`c`.`checked_out_time`,`c`.`created_time`,`c`.`created_user_id`,`c`.`description`,`c`.`extension`,`c`.`hits`,`c`.`language`,`c`.`level`,`c`.`lft`,`c`.`metadata`,`c`.`metadesc`,`c`.`metakey`,`c`.`modified_time`,`c`.`note`,`c`.`params`,`c`.`parent_id`,`c`.`path`,`c`.`published`,`c`.`rgt`,`c`.`title`,`c`.`modified_user_id`,`c`.`version`, CASE WHEN CHAR_LENGTH(`c`.`alias`) != 0 THEN CONCAT_WS(':', `c`.`id`, `c`.`alias`) ELSE `c`.`id` END as `slug` FROM `incbmx_categories` AS `s` INNER JOIN `incbmx_categories` AS `c` ON (`s`.`lft` <= `c`.`lft` AND `c`.`lft` < `s`.`rgt`) OR (`c`.`lft` < `s`.`lft` AND `s`.`rgt` < `c`.`rgt`) WHERE (`c`.`extension` = :extension OR `c`.`extension` = 'system') AND `c`.`access` IN (:preparedArray1,:preparedArray2) AND `c`.`published` = 1 AND `s`.`id` = :id ORDER BY `c`.`lft`191μs3.92KBParams/libraries/src/Categories/Categories.php:375Copy
  • SELECT `m`.`tag_id`,`t`.* FROM `incbmx_contentitem_tag_map` AS `m` INNER JOIN `incbmx_tags` AS `t` ON `m`.`tag_id` = `t`.`id` WHERE `m`.`type_alias` = :contentType AND `m`.`content_item_id` = :id AND `t`.`published` = 1 AND `t`.`access` IN (:preparedArray1,:preparedArray2)255μs4KBParams/libraries/src/Helper/TagsHelper.php:388Copy
  • SELECT `c`.`id`,`c`.`asset_id`,`c`.`access`,`c`.`alias`,`c`.`checked_out`,`c`.`checked_out_time`,`c`.`created_time`,`c`.`created_user_id`,`c`.`description`,`c`.`extension`,`c`.`hits`,`c`.`language`,`c`.`level`,`c`.`lft`,`c`.`metadata`,`c`.`metadesc`,`c`.`metakey`,`c`.`modified_time`,`c`.`note`,`c`.`params`,`c`.`parent_id`,`c`.`path`,`c`.`published`,`c`.`rgt`,`c`.`title`,`c`.`modified_user_id`,`c`.`version`, CASE WHEN CHAR_LENGTH(`c`.`alias`) != 0 THEN CONCAT_WS(':', `c`.`id`, `c`.`alias`) ELSE `c`.`id` END as `slug` FROM `incbmx_categories` AS `s` INNER JOIN `incbmx_categories` AS `c` ON (`s`.`lft` <= `c`.`lft` AND `c`.`lft` < `s`.`rgt`) OR (`c`.`lft` < `s`.`lft` AND `s`.`rgt` < `c`.`rgt`) WHERE (`c`.`extension` = :extension OR `c`.`extension` = 'system') AND `c`.`access` IN (:preparedArray1,:preparedArray2) AND `c`.`published` = 1 AND `s`.`id` = :id ORDER BY `c`.`lft`170μs3.92KBParams/libraries/src/Categories/Categories.php:375Copy
  • SELECT DISTINCT a.id, a.title, a.name, a.checked_out, a.checked_out_time, a.note, a.state, a.access, a.created_time, a.created_user_id, a.ordering, a.language, a.fieldparams, a.params, a.type, a.default_value, a.context, a.group_id, a.label, a.description, a.required, a.only_use_in_subform,l.title AS language_title, l.image AS language_image,uc.name AS editor,ag.title AS access_level,ua.name AS author_name,g.title AS group_title, g.access as group_access, g.state AS group_state, g.note as group_note FROM incbmx_fields AS a LEFT JOIN `incbmx_languages` AS l ON l.lang_code = a.language LEFT JOIN incbmx_users AS uc ON uc.id=a.checked_out LEFT JOIN incbmx_viewlevels AS ag ON ag.id = a.access LEFT JOIN incbmx_users AS ua ON ua.id = a.created_user_id LEFT JOIN incbmx_fields_groups AS g ON g.id = a.group_id LEFT JOIN `incbmx_fields_categories` AS fc ON fc.field_id = a.id WHERE ( (`a`.`context` = :context AND (`fc`.`category_id` IS NULL OR `fc`.`category_id` IN (:preparedArray1,:preparedArray2,:preparedArray3)) AND `a`.`access` IN (:preparedArray4,:preparedArray5)) AND (`a`.`group_id` = 0 OR `g`.`access` IN (:preparedArray6,:preparedArray7)) AND `a`.`state` = :state) AND (`a`.`group_id` = 0 OR `g`.`state` = :gstate) AND `a`.`only_use_in_subform` = :only_use_in_subform ORDER BY a.ordering ASC386μs4.81KBParams/libraries/src/MVC/Model/BaseDatabaseModel.php:164Copy
  • SELECT `c`.`id`,`c`.`asset_id`,`c`.`access`,`c`.`alias`,`c`.`checked_out`,`c`.`checked_out_time`,`c`.`created_time`,`c`.`created_user_id`,`c`.`description`,`c`.`extension`,`c`.`hits`,`c`.`language`,`c`.`level`,`c`.`lft`,`c`.`metadata`,`c`.`metadesc`,`c`.`metakey`,`c`.`modified_time`,`c`.`note`,`c`.`params`,`c`.`parent_id`,`c`.`path`,`c`.`published`,`c`.`rgt`,`c`.`title`,`c`.`modified_user_id`,`c`.`version`, CASE WHEN CHAR_LENGTH(`c`.`alias`) != 0 THEN CONCAT_WS(':', `c`.`id`, `c`.`alias`) ELSE `c`.`id` END as `slug` FROM `incbmx_categories` AS `s` INNER JOIN `incbmx_categories` AS `c` ON (`s`.`lft` <= `c`.`lft` AND `c`.`lft` < `s`.`rgt`) OR (`c`.`lft` < `s`.`lft` AND `s`.`rgt` < `c`.`rgt`) WHERE (`c`.`extension` = :extension OR `c`.`extension` = 'system') AND `c`.`access` IN (:preparedArray1,:preparedArray2) AND `c`.`published` = 1 AND `s`.`id` = :id ORDER BY `c`.`lft`202μs3.92KBParams/libraries/src/Categories/Categories.php:375Copy
  • SELECT `name`,`element` FROM `incbmx_extensions` WHERE `type` = 'plugin' AND `folder` = 'finder' AND `enabled` = 1170μs1.89KB/administrator/components/com_finder/src/Helper/LanguageHelper.php:135Copy
  • SELECT `title` FROM `incbmx_finder_taxonomy` WHERE `parent_id` = 1 AND `state` = 1 AND `access` IN (1,5)98μs648B/administrator/components/com_finder/src/Indexer/Taxonomy.php:325Copy
  • SELECT * FROM `incbmx_schemaorg` WHERE `itemId` = :itemId AND `context` = :context70μs1.55KBParams/plugins/system/schemaorg/src/Extension/Schemaorg.php:403Copy
  • SELECT `a`.`id`,`a`.`asset_id`,`a`.`title`,`a`.`alias`,`a`.`introtext`,`a`.`fulltext`,`a`.`state`,`a`.`catid`,`a`.`created`,`a`.`created_by`,`a`.`created_by_alias`,`a`.`modified`,`a`.`modified_by`,`a`.`checked_out`,`a`.`checked_out_time`,`a`.`publish_up`,`a`.`publish_down`,`a`.`images`,`a`.`urls`,`a`.`attribs`,`a`.`version`,`a`.`ordering`,`a`.`metakey`,`a`.`metadesc`,`a`.`access`,`a`.`hits`,`a`.`metadata`,`a`.`featured`,`a`.`language`,`fp`.`featured_up`,`fp`.`featured_down`,`c`.`title` AS `category_title`,`c`.`alias` AS `category_alias`,`c`.`access` AS `category_access`,`c`.`language` AS `category_language`,`fp`.`ordering`,`u`.`name` AS `author`,`parent`.`title` AS `parent_title`,`parent`.`id` AS `parent_id`,`parent`.`path` AS `parent_route`,`parent`.`alias` AS `parent_alias`,`parent`.`language` AS `parent_language`,ROUND(`v`.`rating_sum` / `v`.`rating_count`, 1) AS `rating`,`v`.`rating_count` AS `rating_count` FROM `incbmx_content` AS `a` INNER JOIN `incbmx_categories` AS `c` ON `c`.`id` = `a`.`catid` LEFT JOIN `incbmx_content_frontpage` AS `fp` ON `fp`.`content_id` = `a`.`id` LEFT JOIN `incbmx_users` AS `u` ON `u`.`id` = `a`.`created_by` LEFT JOIN `incbmx_categories` AS `parent` ON `parent`.`id` = `c`.`parent_id` LEFT JOIN `incbmx_content_rating` AS `v` ON `a`.`id` = `v`.`content_id` WHERE ( (`a`.`id` = :pk AND `c`.`published` > 0) AND (`a`.`publish_up` IS NULL OR `a`.`publish_up` <= :publishUp)) AND (`a`.`publish_down` IS NULL OR `a`.`publish_down` >= :publishDown) AND `a`.`state` IN (:preparedArray1,:preparedArray2)183μs6.17KBParams/components/com_content/src/Model/ArticleModel.php:215Copy
  • SELECT SUM(CASE WHEN `a`.`next_execution` <= :now THEN 1 ELSE 0 END) AS due_count,SUM(CASE WHEN `a`.`locked` IS NULL THEN 0 ELSE 1 END) AS locked_count FROM `incbmx_scheduler_tasks` AS `a` WHERE `a`.`state` = 181μs1.37KBParams/administrator/components/com_scheduler/src/Model/TasksModel.php:465Copy