Electronics & Computers

LED Emergency Light Circuit

noreply@blogger.com (Rawbinn) — Sun, 09 Jan 2011 19:48:00 +0000

This LED emergency light project is simple, cheap and easy
to build. The circuit do the charging of the battery and when the
main source is not available such as in brownouts, the white LEDs
automatically turn on.
LED emergency light schematic diagram

Initially, the voltage output from 220V to 12V converter is fed to the
input of LM317 regulator. Then this voltage is regulated down to 7.37V
using 240 ohms and 1.2K resistor combination (see LM317 Calculator).
At this instant, the battery is in charging mode and the transistor Q1 is
off. Indicator LED serves two purpose, one primarily is to give us idea
that the battery is charging and another is to ensure that the Q1 is off.
During brownouts, the transistor Q1 is on and delivers current
to 16 white LED of about 20mA each, thus a fully charged battery
(6V/4.5Ah) can last up to 14 hours.

The charger has no built in over-current control but still it protects the
battery from overcharging since the charging voltage is set only to 7.4V.

Project materials:
1pc - transformer - 220V to 12V-0-12V , center tap 12VA
16pc - 120 ohms resistor 1/4 W
16pc - white LED min 3V@30mA
1pc - red LED
1pc - 1000uF/25V electrolytic capacitor
3pc - 1N4001 diode
1pc - LM317 regulator
1pc - 1.5K resistor 1/4W
1pc - 240 ohms resistor 1/4W
1pc - 1.2k resistor 1/4W
1pc - 9012 pnp transistor or any of much higher capacity
1pc - 6V 4.5ah battery

Inside of an Inverter.

noreply@blogger.com (Rawbinn) — Sun, 09 Jan 2011 19:30:00 +0000

Customize Your Google Background

noreply@blogger.com (Rawbinn) — Sun, 09 Jan 2011 19:29:00 +0000

Google is introducing a new feature that brings the personalization of Google a notch higher. Now, Google lets you add your favorite photo or image as the background of the Google homepage, replacing the plain white default of Google. Photos can be chosen from your computer, your own Picasa Web Album or a public gallery hosted by Picasa which includes a selection of beautiful photos.

How to set background image

Sign in to your Google Account in the top right corner of the Google homepage. Don't have one? It's easy to create a Google Account.
Click Change background image in the bottom left corner of the Google homepage.
Choose where to select your background image:
From my computer: Select an image saved on your computer.
My Picasa Web photos: Select an image from your Picasa Web Albums.
Public gallery: Select from public photos featured in Picasa Web Albums.
Editor's picks: Select from a set of Google recommended images.
Once you've chosen your image, click Select at the bottom of the window. It may take a moment before your new Google homepage background appears.

You can remove your background image at any time by clicking Remove background image in the bottom left corner of the homepage.

circuit diagram:12dc to 220ac converter

noreply@blogger.com (Rawbinn) — Sun, 09 Jan 2011 18:50:00 +0000

You want to convert 12vdc to 220vac, 300w. Then this schematic diagram will helps you. It can be used for home appliances, lamps, electric radio, mobile charger etc.
Part Total Qty.Description

C1, C22 = 68 uf, 25 V Tantalum Capacitor

R1, R22 =10 Ohm, 5 Watt Resistor

R3, R42 =180 Ohm, 1 Watt Resistor

D1, D22 =HEP 154 Silicon Diode

Q1, Q22 =2N3055 NPN Transistor (see "Notes")

T11 =24V, Center Tapped Transformer (see "Notes")

MISC1 =Wire, Case, Receptical (For Output)

Javascript tricks/pranks

noreply@blogger.com (Rawbinn) — Sun, 09 Jan 2011 18:34:00 +0000

Trick to move pictures in sites.
Type this code where you type url address.
javascript:R=0; x1=.1; y1=.05; x2=.25; y2=.24; x3=1.6; y3=.24; x4=300; y4=200; x5=300; y5=200; DI=document.images; DIL=DI.length; function A(){for(i=0; i-DIL; i++){DIS=DI[ i ].style; DIS.position='absolute'; DIS.left=Math.sin(R*x1+i*x2+x3)*x4+x5; DIS.top=Math.cos(R*y1+i*y2+y3)*y4+y5}R++}setInterval('A()',5); void(0);

The code to edit the site

noreply@blogger.com (Rawbinn) — Sun, 09 Jan 2011 18:31:00 +0000

Go to the site you wanna change. Go to URL, delete what's in there, paste below code, and press enter and just change what you want.
javascript:document.body.contentEditable ='true'; document.designMode ='on'; void 0

12Volt to 9Volt DC Converter

noreply@blogger.com (Rawbinn) — Sun, 09 Jan 2011 18:15:00 +0000

Parts List:
R1 = 560 ohm
C1 = 1000uF/40V, Electrolytic
C2 = 10uF/25V, Electrolytic
C3 = 330nF, Ceramic
Z1 = 9.1V, 1watt zener
Q1 = ECG184, NTE184

Notes:
To get a more precise output voltage, replace zener diode Z1 with 10V and R1 with a 1Kilo ohm potentiometer. A Coolrib for Q1 is optional but highly recommended. You can replace Q1 for a more robust type to get more output amps depending on your requirements. Simple circuit to power your 9 volt cassette recorder and other stuff.

From : http://www.uoguelph.ca/~antoon/circ/car912.htm

Convert: 6vdc to12vdc

noreply@blogger.com (Rawbinn) — Sun, 09 Jan 2011 17:09:00 +0000

If you are in tour, camping, picnic it is helpful for you. you can conver 6VDC to 12VDC.Here is the circuit diagram of 6VDC to 12VDC Converter. With this circuit, you can doubled the input voltage of 6V DC to become 800mA of 12V DC output voltage.

Parts:
R1, R4 = 2.2K
R2, R3 = 4.7K
R5 = 1K
R6 = 1.5K
R7 = 33K
R8 = 10K
C1,C2 = 0.1uF C3 = 470uF/25V
D1 = 1N914
D2 = 1N4004
D3 = 12V 400mW Zener Diode
Q1, Q2, Q4 = BC547
Q3 = BD679