for large indoor applications. Cameras used outdoors or in severe
environments require protective housings (see paragraph titled "Housings").
Figure 31 depicts these two formats and other camera components. Once
format is established, cameras are classified as to vidicon type or solid
state. The types of cameras discussed below are currently in use. Camera
power requirements are 110 volts ac or 220 volts ac and 24 volts dc.
Alternating current is used normally.
220.127.116.11 Standard Vidicon. The standard vidicon tube is the most widely
used image tube for CCTV. In 24-hour continuous use, it will last up to 6
months. It is a vacuum tube with a target made of antimony trisulfide