Existen componentes electrónicos, como lámparas de neón, transistores de unión única (TUJ), transistores de unión única programables (PUT), SCR, Sidacs y otros, que presentan en su curva característica una región de resistencia negativa que les otorga propiedades especiales.

Estas propiedades permiten su uso en la generación de formas de onda en un circuito llamado "oscilador de relajación".

Básicamente, estos osciladores aprovechan las características de activación del componente, que ocurren cuando la tensión voltaje aplicado alcanza ciertos valores.

Estos osciladores son entonces del tipo RC en el que un capacitor se carga a través de una resistencia y la velocidad con la que esto ocurre determina la frecuencia de funcionamiento del circuito.

En la figura 1 tenemos una configuración básica de un oscilador de relajación en su forma más tradicional, que utiliza una lámpara de neón.

 


 

 

 

En este circuito, el capacitor se carga a través de un resistor hasta la tensión de activación de la lámpara de neón, del orden de 80 V.

Cuando esto ocurre, el gas dentro de la lámpara se ioniza y conduce, descargando el condensador.

Cuando la tensión en el capacitor cae por debajo del valor necesario para mantener la ionización, la lámpara se apaga y el condensador puede votar para que el resistor lo cargue.

El ciclo de carga y descarga continúa mientras haya tensión disponible para cargar el capacitor, generando una señal cuya forma de onda se muestra en la figura 2.

 


 

 

 

Tenga en cuenta que el tiempo de descarga es mucho menor que el tiempo de carga, lo que hace que se generen pulsos y señales de diente de sierra en un circuito de este tipo.

La frecuencia máxima que alcanza un circuito de este tipo es baja, del orden de unas pocas decenas de kilohertz como máximo, sin embargo, con dispositivos más rápidos como SIDAC y otros, se pueden lograr valores más altos.

En la figura 3 tenemos un circuito completo de un oscilador con un transistor unijuntura que tiene las mismas características que la lámpara de neón.

 


 

 

Cuando la tensión en el capacitor alcanza el valor de disparo, el transistor de unión simple conduce intensamente entre el emisor y la base B1, produciendo así su descarga con la generación de un pulso.

El transistor unijuntura tampoco puede generar señales en frecuencias que superan algunas decenas de kilohertz.

La frecuencia de dicho circuito se puede calcular utilizando una fórmula empírica que se detalla a continuación:

 

f = 1 / (1.1 x R x C)

 

Donde:

f = frecuencia en hertz (Hz)

R = resistencia en ohms

C = capacitancia en Farads (F)

En una aplicación como temporizador, el circuito produce un pulso después de un intervalo de tiempo dado por;

 

T = 1.1 x R x C

 

Donde:

T es el período de retraso en segundos

 

Para un resistor de 2 M ohms y un capacitor de 10 uF, el tiempo obtenido para producir el pulso será de aproximadamente 22 segundos.

En la práctica, este valor puede ser un poco menor de lo esperado, dadas las tolerancias de los componentes utilizados.

 

Ver también:

• Osciladores

• Constante de tiempo

• Lámpara de neón

• Transistor unijuntura

• SIDAC

• Ionización

 

18.871MBMemory Usage46.35msRequest 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" => 1749318040 "last" => 1749318040...
registry
array:3 [ "data" => [] "initialized" => false "separator" => "." ]
user
array:21 [ "id" => 0 "name" => null "username" => null "email" => null "password" => "***r...
  • afterLoad (85.59KB) (1.29ms)
  • afterInitialise (1.14MB) (5.83ms)
  • afterRoute (123.32KB) (1.38ms)
  • beforeRenderComponent com_content (101.08KB) (585μs)
  • Before Access::preloadComponents (all components) (33.45KB) (385μs)
  • After Access::preloadComponents (all components) (107.06KB) (508μs)
  • Before Access::preloadPermissions (com_content) (1.57KB) (8μs)
  • After Access::preloadPermissions (com_content) (16.22MB) (19.74ms)
  • Before Access::getAssetRules (id:104 name:com_content.article.9808) (514.65KB) (690μs)
  • After Access::getAssetRules (id:104 name:com_content.article.9808) (7.38KB) (88μs)
  • afterRenderComponent com_content (373.16KB) (7.62ms)
  • afterDispatch (2.25KB) (70μs)
  • beforeRenderRawModule mod_articles_category (Banco de Circuitos) (358.53KB) (1.81ms)
  • afterRenderRawModule mod_articles_category (Banco de Circuitos) (15.43KB) (468μs)
  • beforeRenderRawModule mod_finder (Busca_inteligente) (5.9KB) (93μs)
  • afterRenderRawModule mod_finder (Busca_inteligente) (129.21KB) (1.27ms)
  • beforeRenderModule mod_articles_category (Banco de Circuitos) (9.27KB) (604μs)
  • afterRenderModule mod_articles_category (Banco de Circuitos) (5.47KB) (96μs)
  • beforeRenderModule mod_finder (Busca_inteligente) (6.64KB) (189μs)
  • afterRenderModule mod_finder (Busca_inteligente) (4.44KB) (51μs)
  • afterRender (250.06KB) (3.44ms)
  • 1 x After Access::preloadPermissions (com_content) (16.22MB) (42.59%)
    19.74ms
    1 x afterRenderComponent com_content (373.16KB) (16.45%)
    7.62ms
    1 x afterInitialise (1.14MB) (12.57%)
    5.83ms
    1 x afterRender (250.06KB) (7.42%)
    3.44ms
    1 x beforeRenderRawModule mod_articles_category (Banco de Circuitos) (358.53KB) (3.91%)
    1.81ms
    1 x afterRoute (123.32KB) (2.97%)
    1.38ms
    1 x afterLoad (85.59KB) (2.78%)
    1.29ms
    1 x afterRenderRawModule mod_finder (Busca_inteligente) (129.21KB) (2.75%)
    1.27ms
    1 x Before Access::getAssetRules (id:104 name:com_content.article.9808) (514.65KB) (1.49%)
    690μs
    1 x beforeRenderModule mod_articles_category (Banco de Circuitos) (9.27KB) (1.3%)
    604μs
    1 x beforeRenderComponent com_content (101.08KB) (1.26%)
    585μs
    1 x After Access::preloadComponents (all components) (107.06KB) (1.1%)
    508μs
    1 x afterRenderRawModule mod_articles_category (Banco de Circuitos) (15.43KB) (1.01%)
    468μs
    1 x Before Access::preloadComponents (all components) (33.45KB) (0.83%)
    385μs
    1 x beforeRenderModule mod_finder (Busca_inteligente) (6.64KB) (0.41%)
    189μs
    1 x afterRenderModule mod_articles_category (Banco de Circuitos) (5.47KB) (0.21%)
    96μs
    1 x beforeRenderRawModule mod_finder (Busca_inteligente) (5.9KB) (0.2%)
    93μs
    1 x After Access::getAssetRules (id:104 name:com_content.article.9808) (7.38KB) (0.19%)
    88μs
    1 x afterDispatch (2.25KB) (0.15%)
    70μs
    1 x afterRenderModule mod_finder (Busca_inteligente) (4.44KB) (0.11%)
    51μs
    1 x Before Access::preloadPermissions (com_content) (1.57KB) (0.02%)
    8μs
21 statements were executed, 5 of which were duplicates, 16 unique11.37ms1.57MB
  • SELECT @@SESSION.sql_mode;31μs968B/libraries/src/Session/MetadataManager.php:184Copy
  • SELECT `session_id` FROM `incbmx_session` WHERE `session_id` = :session_id LIMIT 191μs1.3KBParams/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)204μs944BParams/libraries/src/Session/MetadataManager.php:260Copy
  • SELECT `id`,`rules` FROM `incbmx_viewlevels`50μs656B/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` = :guest74μs1.64KBParams/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`268μs3.98KBParams/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)348μs7.44KBParams/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` = 07.78ms1.48MBParams/libraries/src/Access/Access.php:301Copy
  • SHOW FULL COLUMNS FROM `incbmx_content`372μs2.39KB/libraries/vendor/joomla/database/src/Mysqli/MysqliDriver.php:587Copy
  • UPDATE `incbmx_content` SET `hits` = (`hits` + 1) WHERE `id` = '9808'224μs48B/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)190μs22.13KBParams/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`222μs3.92KBParams/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)235μs3.97KBParams/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`159μs3.92KBParams/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 ASC402μs4.81KBParams/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`176μs3.92KBParams/libraries/src/Categories/Categories.php:375Copy
  • SELECT `name`,`element` FROM `incbmx_extensions` WHERE `type` = 'plugin' AND `folder` = 'finder' AND `enabled` = 1153μs1.89KB/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)90μs648B/administrator/components/com_finder/src/Indexer/Taxonomy.php:325Copy
  • SELECT * FROM `incbmx_schemaorg` WHERE `itemId` = :itemId AND `context` = :context64μs1.55KBParams/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)160μs22.17KBParams/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` = 174μs1.37KBParams/administrator/components/com_scheduler/src/Model/TasksModel.php:465Copy