Wednesday, May 5, 2010

What Does mAh Stand For

The letters “mAh” stand for milliampere hours – it is how a battery’s energy storage capacity is measured. This also tells us how many electrical currents are released in an hour.

m = milli = 1/1000
A = ampere, a unit of electrical current (usually shortened to “amp”)
h = hour
Therefore mAh means 1/1000 of an ampere for an hour. It is equal to 3.6 coulombs.

Tuesday, May 4, 2010

VHF and UHF TV Antenna

Television antennas usually has a pair of metal rods (made primarily of alumunium) extending from a boom. The quality of the antenna is depends on how well anodized the metal is. When the metal oxidizes, you will almost always experience inadequate reception. Outdoor TV antennas are more prone to wear than their indoor counterparts although outdoor TV antennas provide additional reliability and clarity. The main factors determining reception are the direction and distance from the television station transmitters to your antenna, as well as the transmitter’s power. Indoor antennas are gennerally small, designed to be placed on or near your TV and can be affected by wall insulation, roofing materials, plumbing, electrical wiring and even people moving around a room. Other sources of household interference include computers, fluorescent light, and cordless phones.

Saturday, May 1, 2010

What is IP Camera

An IP camera is a camera that uses the Web to transmit images and control signals. It transmits data in a digital format over an Ethernet connection. IP stands for Internet Protocol, and IP camera is also commonly called an IP network camera. It is usually used as a security camera and surveillance. The images quality are better than analog and it can be installed alone or in a group. They are normally mounted and connected to a digital video recorder (DVR) or linked to a network video recorder (NVR) to form a video surveillance system. If the IP camera is connected to a computer network, it can be viewed and managed over the internet from anyplace in the world. It simply needs access to a conventional Web browser and every IP camera on a network has its own unique network functions and address as a video server. The camera type have a wide variety of protocols including TCP/IP and HTTP.