Free Electronic Circuits,Schematic Diagram,Circuit Diagrams

Thumbnail image that says sleek button using photoshop that links to a Photoshop tutoril. free, electronic circuit, circuit diagram, circuit schematic, schematic diagram, electronic diagram, audio, amplifier, power supply, guitar effect, current loop, current limiter, video, receiver, transmitter, transceiver, transistor, radio frequency, rf, active filters, digital, analog circuit, pwm, micro controller Free download

Free Electronic Circuits,Schematic Diagram,Circuit Diagrams

External links - Jqueryelectronics circuit,circuits,schematic diagram,circuit design,circuit diagram, circuit

Electronic Circuit,Schematic Diagram,Circuit Diagrams

External links - Jqueryelectronic circuit, circuit diagram, circuit schematic, schematic diagram, electronic diagram, audio, amplifier, power supply, guitar effect, current loop, current limiter, video, receiver, transmitter, transceiver, transistor, radio frequency, rf, active filters, digital, analog circuit, pwm, micro controller Free download

Best Song Lyrics Collection

External links - JqueryFind The Music Lyrics To Any Song! It's Free DAILY UPDATED! One of the largest,most accurate, browsable and searchable song lyrics source on the net. lyric, lyrics, song, music, song lyrics, music lyrics

Saturday, September 19, 2009

Contactless telephone ringer circuit


The contact less telephone ringer circuit can produce a ring as well as a visual indication when a call comes.The main advantage is that since there is no direct contact between the phone line and the circuit there is no chance for a loading or disturbance in the telephone line.






When the telephone rings 60 Hz AC signal is generated which produces a proportional magnetic field around the telephone lines.These magnetic field will be picked up by the coil L1 due to electromagnetic induction.A proportional voltage is developed across L1 and it will bias transistor Q1 to ON.This results in the conduction of transistors Q2,Q3 andQ4.The buzzer will ring and the LED will glow.The switch S1 acts as an ON/OFF switch.




Notes.

* For L1 make 50 close turns of 28 SWG enameled copper wire on any of the two telephone wires.Connect one end of the coil to base of Q1 and leave other end free.
* If the circuit not works by try by changing the end of the L1 connected to base of Q1.
* A 9V transistor radio battery can be used as the power source.
* Assemble the circuit on a good quality PCB or common board.
* Use of this type or any other devices other than the allowed telephones and devices with the telephone line may be a law violation in some nations.Check it properly before trying.

0 comments:

Post a Comment | Feed

Post a Comment



.
.
.
.
.
 
TopBlogDir.blogspot.com button Top Blogs Technology Blogs Technology Blogs Add to My Yahoo! On our way to 1,000,000 rss feeds - millionrss.com Blog Search Blog Directory & Search engine LocalSubmit.com : search engine submissions and website promotion with free advice TopOfBlogs SonicRun.com blog search directory Submit your website to 20 Search Engines - FREE with ineedhits! Download Juice, the cross-platform podcast receiver
Today.com SoMuch.com: Internet Links Directory NZPAGES - Your New Zealand Web Site Directory BlogRankers.com Make Money Blogging

Search Optimization, Search Engine Optimization

A link

El directorio y buscador de Mexico Blog Search Engine Top Blogs http://www.freesearchenginesubmission.infovisiter ici Cheap Hotels Online blog directory ping fast  my blog, website, or RSS feed for Free Green-Tech blog
State Your Blog - Blog Top Sites - www.stateyourblog.com
http://www.freedomain.co.nr Increase Page Rank Cyndi's List of Genealogy Sites
 on the Internet Cyndi's List of Genealogy Sites on the Internet Search Engine Submission - AddMe http://www.freesearchenginesubmission.infoclic pour info Search Engine Marketing and Optimization

Thank U & Come Again.....


Search Engine Optimization and SEO Tools
Submit ExpressSearch Engine Marketing

FREE CIRCUIT DIAGRAMS 4U Copyright © 2009 REDHAT Dashboard Designed by SAER