A solid state relay is a device that controls voltage to allow or prevent a voltage or current from passing through a circuit without using any moving parts. Solid state relays are commonly found in control systems that use large amounts of power and must be switched on and off on a regular basis. Solid state relays can be used for a wide variety of purposes and can be constructed in different ways. How a Solid State Relay Works Solid state relays consist of a control switch that produces an Read More

The usable FTP commands will differ from one FTP client to the next, but these are a set of fairly standard FTP commands as implemented in the FreeBSD FTP client. ! [command [args]] Invoke an interactive shell on the local machine. If there are arguments, the first is taken to be a command to execute directly, with the rest of the arguments as its arguments. $ macro-name [args] Execute the macro macro-name that was defined with the macdef command. Arguments are passed to the macro unglobbed. account [passwd] Supply a Read More

MAC Address filtering is a technique that is implemented on many wireless networks to filter which devices are able to connect to the wireless network. MAC Address filtering allows an administrator to allow specific devices to connect to the network while blocking all other devices. MAC Address filtering is a free service provided by most routers and/or access points and prevents unauthorized users from downloading illegal content, accessing network resources, and using additional bandwidth.   How MAC Address Filtering Works MAC Address filtering is accessible through most routers and can Read More

Infrared light is a form of electromagnetic waves. In its visible form, infrared can be seen as red or violet. Visible infrared waves are very short, measuring about 750 nm in length; longer infrared waves which are closest to microwaves are about 1mm in length. Infrared Waves While most infrared wave lengths give off heat, you are probably aware of one of the most popular uses of infrared wave lengths- the TV remote control. Your remote control works via short infrared wave lengths. Your TV remote is able to produce Read More

One of the nice things about having a scanner is that you are able to take a physical document, put it on the scanner and with a push of the button, have it now available on your computer as an image. This is different from a copier because instead of creating identical hard copies, the scanner takes an identical electronic copy to work with in a picture editing software. How to Scan a Document The first step in scanning a document is ensuring that the scanner is installed and hooked Read More

Ultrasound works in the same fashion that sonar works for ships at sea. They send out a sound signal and it bounces back. However, when it bounces back, it bounces back with information on what the shape is. Therefore, if there was a deep underwater mountain, the sound would signal that there was a mountain there. If there are twins inside a mother's womb, the ultrasound will do the same thing. For an ultrasound to even work, there needs to be a transducer. This is the machine used to view Read More

192.168.0.1 is a private IP address that is commonly used by Netgear and D-Link routers. The Netgear and D-Link brands are competitors to the Linksys division of Cisco, Incorporated and make a large number of the Internet routers used world-wide. The network address is not granted to the Netgear and D-Link companies exclusively; however, as other major router manufacturers are free to choose to use same default address if desired. If there is another router installed on a local network that uses the same default IP, it may be changed Read More

Accelerometers are electromechanical devices that measure the force of acceleration. This force can be dynamic (i.e the accelerometer being moved or vibrations cause it) or static (such as the force of gravity) in nature. The devices have a number of uses, such as determining the device angle or aspect with respect to the Earth, determining whether a vehicle or other structure is moving horizontally, and vibration measurement. How are Accelerometers Used? Accelerometers help engineers and mechanics determine problems in vehicle engines through vibration analysis. They determine existing damage as well Read More

The Linear Tape-Open (LTO) was introduced by IBM, Seagate and Hewlett-Packard in 1998 as a powerful and scalable open tape architecture aimed at meeting the rising storage demands of contemporary servers. Brought forth as a means to supersede the Digital Linear Tape (DLT) format, up to 200 GB of capacity for data storage per cartridge was made possible at that time. The first generation of LTO tape stored data in 384 data tracks, which were divided into four data bands of 96 tracks each. The four data bands would be Read More

Disk imaging refers to copying the contents of a data storage device or medium, and transferring this to another, similar medium or device. In its original context, disk imaging implies the creation of an exact duplicate of a computer's hard disk drive – including its programs, setup and data then storing this in a special, compressed file format. Disk imaging aims to provide the user with an exact replica of a computer's systems and data – needed in case of a catastrophic disk crash where the user needs to recover Read More