A photoresistor (or light-dependent resistor, LDR, or photoconductivecell) is a light-controlled variable resistor. The resistance of a photoresistor decreases with increasing incident light intensity; in other words, it exhibits photoconductivity. A photoresistor can be applied in light-sensitive detector circuits, and light- and dark-activated switching circuits.
Aror is made of a high resistance semiconductor. In the dark, a photoresistor can have a resistance as high as several megohms (MΩ), while in the light, a photoresistor can have a resistance as low as a few hundred ohms. If incident light on a photoresistor exceeds a certain frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band. The resulting free electrons (and their hole partners) conduct electricity, thereby lowering resistance. The resistance range and sensitivity of a photoresistor can substantially differ among dissimilar devices. Moreover, unique photoresistors may react substantially differently to photons within certain wavelength bands.

A photoelectric device can be either intrinsic or extrinsic. An intrinsic semiconductor has its own charge carriers and is not an efficient semiconductor, for example, silicon. In intrinsic devices the only available electrons are in the valence band, and hence the photon must have enough energy to excite the electron across the entire bandgap. Extrinsic devices have impurities, also called dopants, added whose ground state energy is closer to the conduction band; since the electrons do not have as far to jump, lower energy photons (that is, longer wavelengths and lower frequencies) are sufficient to trigger the device. If a sample of silicon has some of its atoms replaced by phosphorus atoms (impurities), there will be extra electrons available for conduction. This is an example of an extrinsic semiconducto

What You Need:

    Pint glass canning jar with lid
    3 feet insulated copper wire
    6-volt battery
    Thin iron wire (unraveled picture hanging wire works great)

What You Do:

    Cut the copper wire in half and strip at least one inch of insulation off the ends of each length of wire. Next, punch two holes in the jar lid. (You can use a nail for this.) Thread one end of the wire through each hole in the lid.
    Make a hook at the end of each wire (the end that will be inside the jar when you put the lid on). Twist two or three strands of the iron wire together, then twist the ends around the hooks in the copper wire. The iron wire will act as your filament.
    Place the lid (with the filament and wires attached) in the jar and carefully connect the free ends of the copper wire to the terminals on the 6-volt battery. Once both ends are connected to the battery, the current should start flowing, causing the filament to heat up and give off a bright orange glow.

 Your homemade light bulb is working! The light will last for anywhere from a few seconds to a few minutes, depending on your filament. (Note: once your filament is burned out, don't touch it right away - it will be very hot.)

Use Google Photos to find your stolen Android phone

• Your device has access to the internet.
• Enabled ‘Backup & Sync’ option in Google Photos.
• Someone needs to take pictures with your lost device.

1. Visit photos.google.com and log in using your Google Account in which your Android device is logged into.
2. Check if any pictures were taken after your device was stolen.
3. If yes, then click on the image.
4. Now, click on the info icon on the top right corner.
5. In the appearing sidebar you can now see the image’s information including the located where it was taking.

   Can I track my phone if someone made a factory reset?

   That’s an easy one – No. As the name already implies, resetting a phone brings it back to its factory settings. The most important thing you need – connection to your Google account – won’t be there anymore. If you haven’t installed a tracking app with root access, such as Cerberus, then you won’t be able to locate it anymore

   Can I find my phone using my IMEI number?

   Locating your phone with its unique IMEI number isn’t really possible. In some cases, the police can work together with a phone’s provider to locate it using its IMEI number. But don’t think you can just walk into a police station and expect them to do that. A more realistic thing you can do is to block your phone so that no one can use it to make calls, send texts or use the web. To do so, the best thing is to contact your provider.

   By the way, you can find out your phone’s IMEI number by dialing *#06#. This code should work on most phones. Don’t have your device at hand? Here’s how to find the IMEI without having the phone.  

   Things you should do ASAP if you find your device or end up getting a new one

   We received a lot of emails, tweets and comments the last months from people that found their phone thanks to this article. Unfortunately, the majority of the readers isn’t that lucky. Either way, if you found your phone or plan to buy a replacement, you should be well prepared before something like that happens again. Below are two fundamental steps you should take to quickly track down your device should you lose it again.

   1. Most important: Install a tracking app!

   That’s a no-brainer. Having a tracking/anti-theft app on your phone greatly increases the chances of getting it back. There are a lot of different tracking apps but my absolute favorite is Cerberus. It offers a lot of features and is easy to set up. Some of the many options are location tracking, taking videos or pictures with both front or back camera, checking call logs, location history and wiping all data.

   You can get Cerberus one week for free, after which you can purchase a lifetime license for currently 4.99€. It’s not a cheap price but but it’s money well spent.

   2. Activate Android Device Manager (ADM) and Location History

   Make sure that both ADM and Location History are activated. Both tools can be a great help when you lose your device. With ADM you can track your device, make it ring and erase its data. Location history shows you the last recorded locations on a map. If someone stole it, then this could help you (and local authorities) to track down the thief’s home address, for example.

   To activate both services, select “Google Settings” in your app drawer. Select Security and make sure both options below “Android Device Manager” are enabled. Now, go one step back and select “Location”. Click on “Google Location History” and turn it on. Now you’re able to use ADM to track your device and Location History to see its last recorded locations.

   

This article will explain to how u can temporarily generate magnetic field around a metal (  )
In case ure in need of magnetic in picking some metallic materials and you found it difficult to gt magnet around you. You can easily follow dis practical guide and generate your needed (temporal)  magnet around a metal.
 
Materials needed:
Naked copper wire

5v DC battery

A conductor (a screw driver) preferably

Procedure
Step1: Take your naked copper  wire and strip it around the conductor (screw driver)

Note: make sure the two ends of the wire are left out
Step:2  take your battery connect one end of the wire to the positive and the other to the negative

Note: it's note polarize  and
try as much as possible to eliminate sparkling
Step:3  take any conductive substance (e.g metal)   and bring it close to it,  you will surely experience a magnetic force of attraction

 After the volts source as been removed magnetic field still available around the conductor 

Hope it's helpful also fun thanks
And don't forget to comment and share

How to Create a Windows 7 or Windows Vista Password

•     Click on Start and then Control Panel.
• 
  
•     Click on User Accounts and Family Safety (Windows 7) or User Accounts (Windows         Vista)
•   Note: If you don't see this link in Windows 7 it's because you're using Control Panel in a view that just shows icons or links to the applets, and this one isn't included. Open User Accounts instead, and then go on to 
• Step 4.
•     Click on the User Accounts link.
• 
  
•     In the Make changes to your user account area of the User Accounts window, click the Create a password for your account link.
• 
  
•     Type the password you want to use in the first two text boxes.
• 
  
•     Enter something useful in the Type a password hint text box.
• 
  
•     This step is optional but I highly recommend that you use it. If you try logging in to Windows but enter the wrong password, this hint will pop up, hopefully jogging your memory.
• 
  
•     Click the Create password button to confirm your new password.
• 
  
•     You can now close the User Accounts window.

How to Create a Windows XP Password

•     Click on Start and then Control Panel.
• 
  
•     Click on the User Accounts link.
• 
  
•     Note: If you're viewing the Classic View of Control Panel, double-click on the User Accounts icon.
• 
  
•     In the pick an account to change area of the User Accounts window, click on your Windows XP user name.
• 
  
•     Choose the Create a password link.
• 
  
•     In the first two text boxes, enter the password you would like to start using.
• 
  
•     Click the Create Password button to confirm your new password.

    The next screen asks Do you want to make your files and folders private?. If other user accounts will be setup on this PC and you'd like to keep your personal files private from those users, click on the Yes, Make Private button.

    If you're not concerned about this kind of security or this account is the only account on your PC, there's no need to make your files private. In this case, click on the No button.

 

Update  ahead stay tuned 

techworldbaze.blogspot.com

for the applicable codes are listed in the great techworldbaze.blogspot.com.ng  below, but we'll list them here again for your convenience. To enter the following codes, simply open the phone's Phone application and enter each one:

    SW Version, PDA, CSC, and Modem - *#1234#
    SW & HW Info - *#12580369#
    Test mode - *#0*#
    Service Mode - *#197328640#
    ADC Reading - *#0228#
    Bluetooth Test Mode - *#232331#
    Bluetooth Address - *#232337#
    Ciphering Information - *#32489#

If these codes don't work, you may have a fake device. Call Samsung and give them your serial and IMEI numbers so they can verify that your device is indeed genuine. If they find your numbers in your system, your phone is genuine; if not, it's, unfortunately, a fake.

Note: if no related respond was display it's definitely a copy (fake)  phone