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

Friday, September 04, 2009

Fridge Door Alarm Circuit



This circuit, enclosed into a small box, is placed in the fridge near the lamp (if any) or the opening. With the door closed the interior of the fridge is in the dark, the photo resistor R2 presents a high resistance (up to 200K) thus clamping IC1 by holding pin 12 high. When a beam of light enters from the opening, or the fridge lamp illuminates, the photo resistor lowers its resistance (less 2K), pin 12 goes low, IC1 starts counting and, after a preset delay (20 seconds in this case) the piezo sounder beeps for 20 sec. then stops for the same lapse of time and the cycle repeats until the fridge door closes. D2 connected to pin 6 of IC1 allows the piezo sounder beeping 3 times per second.










Parts:

R1 = 10K
R2 = LDR
R3 = 100K
R4 = 100K
D1 = 1N4148

D2 = 1N4148
Q1 = BC337
C1 = 10nF-63V
C2 = 100uF-25V
B1 = 3V Battery

IC1 = 4060 Ripple Counter & Oscillator
IC
BZ1 = Piezo Buzzer Incorporating 3KHZ Oscillator
SW1 = Miniature SPST Slider Switch


Notes:

* Connecting D1 to pin 2 of IC1 will halve the delay time.
* Delay time can be varied changing C1 and/or R3 values. * Any photo resistor type should work. * Quiescent current drawing is negligible, so SW1 can be omitted. * Place the circuit near the lamp and take it away when defrosting, to avoid circuit damage due to excessive moisture. * Do not put this device in the freezer.

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