{"id":374,"date":"2010-06-21T15:04:43","date_gmt":"2010-06-21T13:04:43","guid":{"rendered":"http:\/\/firma.puhy.cz\/?p=374"},"modified":"2010-06-21T15:04:43","modified_gmt":"2010-06-21T13:04:43","slug":"blikac-aktivovany-nizkou-intenzitou-osvetleni","status":"publish","type":"post","link":"https:\/\/www.puhy.cz\/blog\/blikac-aktivovany-nizkou-intenzitou-osvetleni\/","title":{"rendered":"Blika\u010d aktivovan\u00fd n\u00edzkou intenzitou osv\u011btlen\u00ed"},"content":{"rendered":"

Pro jednu aplikaci jsem pot\u0159eboval blika\u010d s LED, kter\u00fd by se aktivoval a\u017e p\u0159i setm\u011bn\u00ed. Po\u017eadavkem bylo nap\u00e1jen\u00ed z baterie – tedy minim\u00e1ln\u00ed odb\u011br proudu. V\u00fdsledkem je velmi jednoduch\u00e9 zapojen\u00ed, kter\u00e9 hrav\u011b sestav\u00ed i za\u010d\u00e1te\u010dn\u00edk.<\/strong><\/p>\n

 <\/p>\n

P\u0159i hled\u00e1n\u00ed vhodn\u00e9ho zapojen\u00ed jsem nejprve narazil na sch\u00e9ma uveden\u00e9 v [1]. Zapojen\u00ed sice fungovalo, ale jak m\u016f\u017eete vid\u011bt na videu n\u00ed\u017ee, nem\u011blo zcela stabiln\u00ed funkci a bylo obt\u00ed\u017en\u00e9 nastavit pr\u00e1h osv\u011btlen\u00ed p\u0159i kter\u00e9m za\u010dalo pracovat. \u010casto z\u016fstalo v neur\u010dit\u00e9m stavu, kdy LED dioda slab\u011b „\u017ehnula“ – to m\u011blo pochopiteln\u011b negativn\u00ed vliv na jeho spot\u0159ebu.<\/p>\n

\"blika\u010d<\/a><\/p>\n

Toto zapojen\u00ed m\u00e1 p\u0159\u00edli\u0161 velk\u00fd odb\u011br v klidov\u00e9m stavu (osv\u011btlen\u00fd fotorezistor)<\/em><\/p>\n

Frekvenci oscilac\u00ed je mo\u017eno ovlivnit zm\u011bnou hodnoty kondenz\u00e1toru mezi emitory tranzistor\u016f. Pr\u00e1h osv\u011btlen\u00ed, p\u0159i kter\u00e9 za\u010dne LED blikat je mo\u017eno nastavit trimrem paraleln\u011b p\u0159ipojen\u00fdm k fotorezistoru. Na m\u00edst\u011b fotorezistoru lze pou\u017e\u00edt i fototranzistor. LED jsem pou\u017eil modrou. Samoz\u0159ejm\u011b je mo\u017eno pou\u017e\u00edt libovolnou LED pokud p\u0159izp\u016fsob\u00edte nap\u00e1jec\u00ed nap\u011bt\u00ed a velikost p\u0159ed\u0159adn\u00e9ho rezistoru (47R).<\/p>\n

<\/object><\/p>\n

Vhodn\u011bj\u0161\u00ed zapojen\u00ed jsem nalezl v [2]. Jedn\u00e1 se o multivibr\u00e1tor s komplement\u00e1rn\u00edmi tranzistory – v p\u0159\u00edpad\u011b deaktivace okoln\u00edm osv\u011btlen\u00edm jsou oba tranzistory uzav\u0159eny a obvodem proch\u00e1z\u00ed pouze mal\u00fd zbytkov\u00fd proud.\u00a0Na m\u00edst\u011b fotorezistoru (prakticky libovoln\u00fd typ) lze pou\u017e\u00edt pochopiteln\u011b i fototranzistor – ten ale mus\u00ed reagovat i na b\u011b\u017en\u00e9 sv\u011btlo, nem\u011bl by m\u00edt IR filtr.\u00a0S uveden\u00fdmi sou\u010d\u00e1stkami jsem p\u0159i osv\u011btlen\u00e9m fototranzistoru (na m\u00edst\u011b R6) nam\u011b\u0159il odb\u011br 5,7uA.<\/p>\n

Hodnota rezistoru R5 odpov\u00edd\u00e1 st\u0159\u00edd\u011b blik\u00e1n\u00ed zhruba 1:1. Sn\u00ed\u017een\u00edm hodnoty R5 na 4k7 lze doc\u00edlit kr\u00e1tk\u00fdch z\u00e1blesk\u016f – sn\u00ed\u017e\u00ed se t\u00edm i st\u0159edn\u00ed hodnota odeb\u00edran\u00e9ho proudu p\u0159i provozu. Rezistor R4 je navr\u017een pro modrou nebo b\u00edlou LED. Pro ostatn\u00ed barvy je pot\u0159eba jeho hodnotu zv\u00fd\u0161it. Funkci obvodu m\u016f\u017eete op\u011bt shl\u00e9dnout na kr\u00e1tk\u00e9m videu.<\/p>\n

\"blika\u010d<\/a><\/p>\n

Multivibr\u00e1tor s komplement\u00e1rn\u00edmi tranzistory – v deaktivovan\u00e9m stavu (osv\u011btlen\u00fd fotorezistor) odeb\u00edr\u00e1 toto zapojen\u00ed pouze 6uA<\/em><\/p>\n

<\/object><\/p>\n

Seznam sou\u010d\u00e1stek<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n
R1<\/td>\n1k<\/td>\n<\/tr>\n
R2<\/td>\n1M<\/td>\n<\/tr>\n
R3<\/td>\n6k8<\/td>\n<\/tr>\n
R4<\/td>\n47R<\/td>\n<\/tr>\n
R5<\/td>\n100k (viz text)<\/td>\n<\/tr>\n
R6<\/td>\nfotorezistor nebo fototranzistor (viz text)<\/td>\n<\/tr>\n
C1<\/td>\n1uF\/6,3V<\/td>\n<\/tr>\n
T1<\/td>\nBC327<\/td>\n<\/tr>\n
T2<\/td>\nBC337<\/td>\n<\/tr>\n
LED<\/td>\nsv\u00edtiv\u00e1 dioda (viz text)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Pou\u017eit\u00e1 literatura<\/h2>\n

[1] Dark-activated LED or Lamp Flasher –\u00a0http:\/\/redcircuits.com\/Page64.htm<\/a><\/p>\n

[2] Blika\u010d \u0159\u00edzen\u00fd okoln\u00edm osv\u011btlen\u00edm – Hermann Schreiber – 50 praktick\u00fdch zapojen\u00ed se sv\u011bteln\u00fdmi diodami, strana 41-42, BEN technick\u00e1 literatura, Praha 1999<\/p>\n","protected":false},"excerpt":{"rendered":"

Dva tranzistorov\u00e9 blika\u010de s minim\u00e1ln\u00edm odb\u011brem, kter\u00e9 se automaticky spust\u00ed p\u0159i setm\u011bn\u00ed.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[14,22,15],"tags":[],"_links":{"self":[{"href":"https:\/\/www.puhy.cz\/blog\/wp-json\/wp\/v2\/posts\/374"}],"collection":[{"href":"https:\/\/www.puhy.cz\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.puhy.cz\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.puhy.cz\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.puhy.cz\/blog\/wp-json\/wp\/v2\/comments?post=374"}],"version-history":[{"count":0,"href":"https:\/\/www.puhy.cz\/blog\/wp-json\/wp\/v2\/posts\/374\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.puhy.cz\/blog\/wp-json\/wp\/v2\/media?parent=374"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.puhy.cz\/blog\/wp-json\/wp\/v2\/categories?post=374"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.puhy.cz\/blog\/wp-json\/wp\/v2\/tags?post=374"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}