A photoresistor is a light-dependent resistor which slowly loses its resistance when exposed to high levels of ultraviolet light. As a result, photoresistors convert light energy into electrical energy. Photoresistors are used in a wide variety of devices to detect the presence of light, control a device, or activate a system. They are usually dependent on external light sources, although they can be connected to a system that produces its own light. Photoresistors are generally made of cadmium sulfide but can be mixed with impurities to allow lower frequencies of light Read More

Skype has grown to be one of the most used applications for real-time video, text, and voice chat. The service allows consumers to make free computer-to-computer calls. Consumers may also make phone calls to all types of telephones at a cost. Skype also has a built-in search function that finds people online on Skype based on their name, email address, or Skype name. The search results can be used to locate specific individuals or other Skype users meeting profile search criteria by region, age, or gender. How to Find People Read More

There are two main types of fiber optic cable, which are single mode and multi-mode. Single mode: Single mode fiber optic cable is a narrow strand that only has one mode of transmission. Single mode fibers are able to transmit at high speeds over long distances as a result of their small core. Because single mode fiber optic cable provides longer transmission distances and faster transmission rates than multi-mode fibers, it costs more than fibers that are multi-mode. Multi-mode: The reason that multi-mode has a lower cost than single mode Read More

A broadcast domain is a logical part of a network (a network segment) in which any network equipment can transmit data directly to other equipment or device without going through a routing device (assuming the devices share the same subnet and use the same gateway; also, they must be in the same VLAN). A more specific broadcast domain definition is the area of the computer network that consists of every single computer or network equipment that can be reached directly by sending a simple frame to the data link layer’s Read More

Hacking as a Destructive Tool The common stance on hacking with the average person is that it is morally wrong. There have been several instances where hacking has proven to have caused problems. Hacking can create a variety of damages to people, groups and systems of broad spectrum. Negative Hacking Interactions: Identity Theft – Some hackers can gain access to sensitive information which could be used to fuel identity theft. This identity theft can cause damages to credit ratings from consumer agencies, run-ins with the law because the person who stole the identity Read More

To sign a Java applet, follow these steps: Compile your applet with `javac` Create a jar file with `jar` Generate a keystore database with `keytool` Sign the jar file with `jarsigner` Export the public key certificate with `keytool’

As more and more people switch to cell phones for communication, many people are opting to use prepaid phone cards rather than signing up for a contract with a service provider. Prepaid phone cards allow users to purchase temporary plans ahead of time and use their minutes from wherever they are without having to worry about overdraft charges and hidden fees. Aside from cell phones, prepaid phone cards also work with pay phones and allow those users to access minutes from their phone card rather than paying a fee on Read More

POP3 is an internet-based standard for retrieval of e-mail by a user from an e-mail server. POP stands for Post Office Protocol. The "3" means it is the third revision of the standard; POP1 and POP2 were made obsolete by POP3, which has been popular for many years now. For users, there are two primary e-mail operations: receiving and sending. When you send mail, your server first checks to make sure you are a valid user, queues up the message to be sent, and then contacts the recipient's mail server. Read More

An RPC (Remote Procedure Call) is a technique used in computer science that allows an application to contact a separate application or service within the same hard drive or on a remote location. While the application initiating the call is known as the “client,” the application or location that is being called is referred to as the “server.” RPC is very popular and is used as a basic framework for several networking systems. For example, RPC is used in print spoolers for communication between a computer and a printer, fax Read More

Domain Name System (DNS) is an Internet Engineering Task Force (IETF) standard name service which enables applications and users to connect to hosts in TCP/IP based networks by specifying a name. DNS makes it possible to assign domain names to organizations independent of the routing of the numerical IP address. DNS is a hierarchically distributed database that creates hierarchical names that can be resolved to IP addresses. The IP addresses are then resolved to MAC addresses. DNS therefore provides the means for naming IP hosts, and for locating IP hosts when they are queried for Read More